Violet light excited white light emitting diodes (LEDs) have attracted widespread attention due to their advantages of tunable color temperature and visual comfort. However, high-performance phosphors suitable for violet light excitation (400-420 nm) have not yet been widely applied on a large scale. One of the key factors regarding the commercial utilizations is the stability. Unfortunately, there still lacks research on this issue. In this study, three rare-earth phosphors suitable for violet light excitation in LEDs were synthesized via a solid-state reaction method, namely K₂CaPO₄F:Eu²⁺, K_1.3Al₁₁O_17+δ:Eu²⁺ and Ca₂YHf₂Al₃O₁₂:Ce³⁺,Tb³⁺. The stability experiments were then conducted under conditions of high temperature and humidity, water immersion, and long-term violet light irradiation from LED chips. The luminescent properties, failure mechanisms, and environmental stability were analyzed. Finally, a white LED device was prepared by combining the as-synthesized three phosphors onto a 400 nm violet light chip. Results demonstrate that the as-synthesized phosphors exhibit not only optimized luminescence performance compared to phosphors prepared in former works, but also a more comprehensive evaluation of environmental stability across different conditions. The white LED device achieves a color rendering index of 93.6, a correlated color temperature of 5151 K and a color coordinate of (0.34, 0.36), showcasing excellent white light illumination performance. Furthermore, the environmental stability of the white LED device is improved compared to individual phosphors. By taking lead in investigating the environmental stability of violet light excited LED phosphors, this work provides valuable insights and guidance for advancing their applications.

Mechanoluminescent (ML) materials, due to their unique mechanical-to-optical energy conversion, hold significant promise in stress sensing and are poised to become the next generation of visual strain-sensing materials. Currently, expanding ML material systems and enhancing their performance remain focal points of research. In this study, a series of Tb³⁺-doped green ML phosphors was synthesized using BaSrGa₄O₈ matrix (hexagonal crystal system, space group P6₃, with a non-centrosymmetric structure) via high-temperature solid-state synthesis. These materials emitted bright green light under various mechanical excitations (tension, compression, and torsion). Clear note mappings were observed by writing B, S, G, O, T, and b on the prepared ML elastomer with a glass rod. By analyzing the colormap, the stress conditions during the writing process could be traced. This is the first observation of ML phenomenon in the above-mentioned matrix doping system. Under 254 nm ultraviolet (UV) excitation, BaSr_1-xGa₄O₈: xTb³⁺ phosphors exhibited bright green emission at 543 nm, which was attributed to ⁵D₄-⁷F₅ transition of Tb³⁺, and shared the same luminescent center as ML. The samples continued to display strong long persistent luminescence after UV irradiation was removed. By combining ML, photoluminescence (PL), and long persistent luminescence (LPL) with thermoluminescence (TL) analysis, further insights into their intrinsic connections were elucidated. In conclusion, this study broadens the range of high-performance ML material systems, showcasing potential applications in visual strain sensing, information security, and anti-counterfeiting.

As an essential candidate for environment-friendly luminescent quantum dots (QDs), CuInS-based QDs have attracted more attention in recent years. However, several drawbacks still hamper their industrial applications, such as lower photoluminescence quantum yield (PLQY), complex synthetic pathways, uncontrollable emission spectra, and insufficient photostability. In this study, CuInZnS@ZnS core/shell QDs was prepared via a one-pot/three-step synthetic scheme with accurate and tunable control of PL spectra. Then their ensemble spectroscopic properties during nucleation formation, alloying, and ZnS shell growth processes were systematically investigated. PL peaks of these QDs can be precisely manipulated from 530 to 850 nm by controlling the stoichiometric ratio of Cu/In, Zn²⁺ doping and ZnS shell growth. In particular, CuInZnS@ZnS QDs possess a significantly long emission lifetime (up to 750 ns), high PLQY (up to 85%), and excellent crystallinity. Their spectroscopic evolution is well validated by Cu-deficient related intragap emission model. By controlling the stoichiometric ratio of Cu/In, two distinct Cu-deficient related emission pathways are established based on the differing oxidation states of Cu defects. Therefore, this work provides deeper insights for fabricating high luminescent ternary or quaternary-alloyed QDs.

Perovskite quantum dots have unique advantages in display. However, their long-term stability at high brightness is still a huge challenge. Therefore, this article focuses on the progress of the regulation of perovskite quantum dots and their luminescent film morphology, explains the influence of long-range ordered perovskite quantum dot films on their electroluminescent properties, and looks forward to the development prospects in improving the electroluminescent stability of perovskite quantum dots.

Bentonite is an abundant, cheap and readily available natural clay mineral, with montmorillonite (MMT) as its main mineral composition. MMT possesses excellent ion exchange, adsorption and ion transport properties due to its unique two-dimensional layered nanostructure, abundant pore structure, and high specific surface area. Moreover, it also possesses excellent thermal, chemical and mechanical stabilities. In recent years, MMT has attracted extensive attention in the field of electrochemical energy storage owing to the above excellent characteristics, especially the inherent fast ion (Li⁺, Na⁺, Zn²⁺, etc.) transport properties. Thus, the bentonite-based functional materials have been widely applied to the key components (i.e., electrodes, polymer electrolytes, and separators) of electrochemical energy storage devices and show good application prospects. In this review, the structure and physicochemical properties of bentonite are firstly introduced, and then the research progress of bentonite-based functional materials in the field of electrochemical energy storage, mainly including metal anodes, lithium-sulfur battery cathodes, solid/gel polymer electrolytes, and polymer separators, is comprehensively summarized. On the basis of these facts, the ion transport promotion mechanism of bentonite-based functional materials during the process of electrochemical energy storage is elaborated. Finally, the current problems and challenges faced by application of bentonite-based materials in electrochemical energy storage devices are pondered, and the possible future research directions are prospected. This review provides useful guidance for the design and development of bentonite-based electrochemical energy storage functional materials.

To further expand the application of advanced ceramic materials in helicopters, this paper reviews their application in helicopter structures both domestically and internationally. It emphasizes the technical maturity and development trends of various ceramic materials in helicopter specific structural applications, such as energy impact protection parts, energy conversion components, and corrosion protection areas. By comparing the gaps between domestic and international use of advanced ceramic materials in helicopter specific structures, the paper provides suggestions for the future development. Recommendations include the use of reaction-sintered contoured integrated opaque armor ceramics and polycrystalline transparent armor ceramics for the high-speed dynamic impact energy protection parts, cermet composite coatings compatible with epoxy resin composite substrates for the low-energy impact protection parts, and hybrid ceramic matrix composite/polymer matrix composite (HCMC-PMC) materials for the thermal shock protection parts. Additionally, multifunctional composite materials, such as high-performance miniature piezoelectric ceramic thin film functional devices and flexible hybrid electronic structures based on micro-piezoelectric ceramic materials, should be developed for the mechanical and electrical energy conversion components. Microwave-absorbing ceramic composites derived from polymer-derived ceramics that are compatible with epoxy resin composite substrates are recommended for the electromagnetic and thermal energy conversion components. Furthermore, high-performance abrasion-resistant and corrosion-resistant Sol-Gel coatings are suggested for the corrosion protection areas. It is also essential to establish a high-speed dynamic energy impact protection mechanism for helicopters, optimize the ballistic performance of protective materials, and develop advanced ceramic materials digital testing and verification technologies, represented by multi-functional composite materials for helicopter specific structures. These efforts will greatly shorten the application cycle of advanced ceramic materials and reduce the verification cost.

Nowadays, we are facing increasingly serious energy and environmental problems, which urgently need more efficient chemical industry technologies to meet the requirements of low cost, high yield and sustainability. Developing efficient catalysts is of great significance for improving production efficiency, expanding economic benefits, optimizing energy structure, and ameliorating industrial structure. Single-atom catalysts (SACs), featuring unique properties arising from their single-atom dispersion on support surface, have demonstrated exceptional activity, selectivity and stability in energy catalysis, environmental catalysis and organic catalysis. Therefore, preparation methods and catalytic mechanisms of SACs have become a hot research topic on the international catalytic community. This review describes three strategies for preparing SACs: bottom-up synthesis, top-down synthesis and quantum dots cross-linking/self-assembly. Specifically, methods such as co-precipitation, immersion, atomic layer deposition, high-temperature atom thermal transfer, and high-temperature pyrolysis are presented in detail. These approaches precisely control the location and distribution of metal atoms, maximizing their utilization and catalytic efficiency. In addition, the challenges and development prospects faced by SACs related to stability, integrated control and industrial scalability are also summarized.

Based on Peltier effect, Bi₂Te₃-based alloy is widely used in commercial solid-state refrigeration at room temperature. The mainstream strategies for enhancing room-temperature thermoelectric performance in Bi₂Te₃ focus on band and microstructure engineering. However, a clear understanding of the modulation of band structure and scattering through such engineering remains still challenging, because the minority carriers compensate partially the overall transport properties for the narrow-gap Bi₂Te₃ at room temperature (known as the bipolar effect). The purpose of this work is to model the transport properties near and far away from the bipolar effect region for Bi₂Te₃-based thermoelectric material by a two-band model taking contributions of both majority and minority carriers into account. This is endowed by shifting the Fermi level from the conduction band to the valence band during the modeling. A large amount of data of Bi₂Te₃-based materials is collected from various studies for the comparison between experimental and predicted properties. The fundamental parameters, such as the density of states effective masses and deformation potential coefficients, of Bi₂Te₃-based materials are quantified. The analysis can help find out the impact factors (e.g. the mobility ratio between conduction and valence bands) for the improvement of thermoelectric properties for Bi₂Te₃-based alloys. This work provides a convenient tool for analyzing and predicting the transport performance even in the presence of bipolar effect, which can facilitate the development of the narrow-gap thermoelectric semiconductors.

Carbide ultra-high temperature ceramics (UHTCs) have emerged as ideal coating materials for the thermal protection systems of hypersonic vehicles due to their high melting point (>3000 ℃), high hardness, low thermal conductivity, excellent heat resistance, and good chemical stability. This review provides a comprehensive overview of structure and properties of carbide UHTCs, namely TiC, ZrC, HfC, NbC, and TaC. Furthermore, it summarizes recent developments in preparation of carbide UHTC coatings using various methods, including chemical vapor deposition, plasma spraying, and solid-phase reaction. Effects of coating microstructure, composition, structural design, and heat flux on the ablation behavior are analyzed. Data from recent literature corroborate that the added second phase can facilitate formation of complex oxides, generate an oxidation layer during ablation to undergo moderate sintering, protect structural integrity, and enhance oxygen barrier properties. Multi-layer structural designs utilize gradient layering and multi-functional structures, which effectively alleviate thermal stress within the coating, suppress crack propagation, and facilitate synergistic enhancing effects among different layers. Finally, the challenges and opportunities in development of carbide UHTC anti-ablation coatings are prospected.

Inorganic non-metallic biomaterial is one of main types of biomaterials, which is widely used in biomedical fields such as tissue repair, tumor therapy, and drug delivery., making an important contribution to national life and health. Research on inorganic non-metallic biomaterials in China is flourishing, but their production and application are still in the stage of overcoming difficulties. To realize the high-quality development of China's inorganic non-metallic biomaterials and improve their hard power to protect national life and health, this paper analyzes hotspots and difficult problems in research and application of China's inorganic non-metallic biomaterials by means of strategic study. Based on current development opportunities and challenges, some suggestions are proposed for the development of inorganic non-metallic biomaterials, such as material design for unique performance, research on materiobiology, exploration of new principles and mechanisms mediated by materials, customization by intelligent personalization, design through big data screening and artificial intelligence, and standardization based evaluation/regulation. This aims to provide guidance for development of inorganic non-metallic biomedical products and push forward scientific research while accumulating talent resources.

SiC ceramics exhibit high strength and thermal stability, rendering them highly suitable for applications in space and thermal components. However, the growing demand for large-sized and complex-shaped SiC ceramics necessitates advanced manufacturing techniques. In comparison to traditional reduction and equal material manufacturing methods, 3D printing technology offers significant advantages in various aspects, such as manufacturing cycle, effective cost, and reliability. There are many 3D printing methods, each with distinct characteristics. Stereolithography (SLA) is capable of achieving high precision and superior surface quality. However, its practical applications often necessitate special design of support structures. Additionally, issues such as residual stress and low solid content significantly hinder its further development. Selective laser sintering (SLS) exhibits strong material compatibility, which is suitable for a wide range of materials, including polymers, metals and ceramics. This technology enables large-scale rapid prototyping at low manufacturing costs. But its surface quality of the formed billet is typically insufficient, which needs additional post-processing. Fused deposition modeling (FDM) though facilitates the preparation of SiC ceramics via reaction sintering, proves unsuitable for constructing large components which restricts its applicability in actual production contexts, due to its inadequate interlayer bonding strength coupled with pronounced surface striations and slower forming speeds. This paper reviews the latest research progresses of 3D-printed SiC ceramics and analyzes the subsequent high-temperature densification treatments of green bodies, along with their fundamental physical properties. Finally, it proposes some prospects of 3D printing of SiC ceramic materials, and strengthens integration of new 3D printing technologies and various printing methods for fine regulation of ceramics’ macro- and micro-structures.

Hydrogen generation from electrolyzed water has received extensive attention in the scientific community due to its green and environmentally friendly properties, as well as the high purity of hydrogen produced. However, the slow oxygen evolution reaction (OER) during electrocatalytic water splitting has significantly hampered the development of hydrogen production, posing numerous challenges in its practical application. In this study, a novel three-dimensional (3D) core-shell heterostructure catalyst with crystalline NiMoO₄ nanorods as “core” and amorphous CoFe-LDH nanosheets as “shell” was successfully fabricated on a conductive nickel foam (NF) substrate by using a combination of hydrothermal and electrodeposition strategy. This special 3D core-shell structure fully stimulates the electrocatalytic potential of NiMoO₄ and CoFe-LDH, which greatly enhances the efficiency of the overall water-splitting. Through the synergistic interaction of NiMoO₄ and amorphous CoFe-LDH, the NiMoO₄@CoFe-LDH/NF nanocatalysts generates more active sites and exhibits highly efficient electron transfer ability and excellent OER electrocatalytic activity. Electrochemical tests show that NiMoO₄@CoFe-LDH/NF exhibits the most excellent electrochemical performance when the electrodeposition time is 60 s. The overpotentials η₁₀ and η₁₀₀ at 10 and 100 mA·cm⁻² are only 168 and 216 mV, respectively, which shows a very small Tafel slope and excellent long-term stability. Meanwhile, the overall water-splitting system of NiMoO₄@CoFe-LDH||NiMoO₄ exhibits a low driving voltage, which can produce a current density of 10 mA·cm⁻² at 1.57 V. In conclusion, this work provides new ideas for design and development of efficient catalytic materials for electrolyzed water.

Compared with traditional lithium-ion batteries, sodium-ion batteries are an ideal alternative due to their cost advantages and sustainable resource supply. At present, the cathode materials for sodium-ion batteries mainly include transition metal oxides, polyanionic compounds and Prussian blue analogues. However, irreversible phase conversion, Jahn-Teller effect and interface instability of cathode materials seriously affect the cycling stability of sodium-ion batteries. In this paper, the research progress and industrialization process of strategies for improving cyclic stability of cathode materials for sodium-ion batteries are systematically introduced. Firstly, the structure as well as advantages and disadvantages of cathode materials is analyzed in detail, and the structural stability, cost and cycling performance are compared. Secondly, the latest research progress of structure optimization and chemical element doping strategies in improving the cycling stability of cathode materials is elaborated in detail, and the interaction between structural stability, electronic conductivity, ion intercalation/deintercalation of cathode materials and electrochemical performance is revealed. Then, the development process and industrialization progress of sodium-ion batteries are summarized. Finally, the significant problems that still need to be addressed for cathode materials and systems for sodium-ion batteries are sorted out and their future developments are prospected, aiming to propel the steady and healthy development of sodium-ion battery industry.

In the process of electrolyzing water to produce hydrogen, the sluggish electrocatalytic kinetics of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) limit the energy conversion efficiency. High-entropy materials have been considered as potential catalysts due to their unique structural features and excellent performance, which could potentially replace traditional metal oxides and precious metals for energy conversion and water electrolysis. Due to the incompatibility between different metals and non-metals, there have been few reports on the synthesis of high-entropy compounds, especially high-entropy metal phosphides. In this study, a series of carbon-based high-entropy alloy phosphide nanoparticles were synthesized using citric acid as complexing agent and ammonium dihydrogen phosphate as phosphorus source via a low-temperature Sol-Gel method with different elemental metals. In 1 mol·L^-1 KOH solution, FeCoNiMoCeP/C exhibited good water electrolysis performance at a current density of 10 mA·cm^-2, with overpotentials of 119 and 240 mV for the HER and OER, respectively. Similarly, in overall water splitting studies, FeCoNiMoCeP/C also showed excellent catalytic activity. When operating at a current density of 10 mA·cm^-2, FeCoNiMoCeP/C required only 1.53 V as the combined anode and cathode voltage for electrolyzing water. This is due to the synergistic effects among the atoms of high-entropy phosphide catalysts which provide more reaction sites to increase reaction activity and selectivity. This study is expected to expand the potential applications of high-entropy alloys in the field of electrocatalysis.

With the rising of the gas inlet temperature in front of the turbine of aero-engine, ceramic matrix composites (CMCs) have emerged as the preferred matrix material for the new generation of high-temperature components in aero-engine due to their light weight, high strength, oxidation resistance, insensitivity to crack, and excellent temperature durability. However, because of their limited resistance to high temperature water vapor and oxygen erosion, development of thermal spray coating technology for hot-end components of CMCs engines has become an urgent challenge to be overcome. In this paper, based upon changes of material selection strategies and application examples of foreign aero-engines, technical limitations of the employed superalloys + film cooling + thermal barrier coatings (TBCs) for hot-end components of aero-engines were analyzed, and technical advantages of the utilized CMCs + appropriate film cooling + environmental barrier coatings (EBCs) were consolidated. Thermal and environmental barrier coatings (TEBCs) and environmental barrier coatings-abradable sealing coatings (EBCs-ASCs) for CMCs were reviewed on the basis of recent research findings from domestic and oversea scholars. Finally, opportunities and challenges associated with thermal spraying EBCs for higher temperature gas flow were analyzed, and the direction of design and preparation on a certain composition and structure for TEBCs was clarified, among which the focal points of future research endeavors were prospected.

High-entropy carbide (HEC) ceramics are distinguished by their high hardness, oxidation resistance, corrosion resistance, wear resistance, and high thermal conductivity, positioning them as promising candidates for application in extreme environments. However, inherent brittleness of these high-entropy ceramics limits their further application. In order to enhance the toughness of HEC ceramics, polycarbosilane (PCS), a precursor of silicon carbide (SiC), was added into the precursor of (Zr, Hf, Nb, Ta, W)C high-entropy ceramic. The in-situ formed SiC (SiC_i) by pyrolysis of PCS can serve as reinforcement for HEC ceramics. The results demonstrate that the volume fraction of SiC in the ceramics obtained from the pyrolysis of PCS is 23.38%. The SiC phases, with an average grain size of 1.19 μm, are evenly distributed in the high-entropy ceramic matrix. The pyrolysis process of ceramic precursors was investigated, revealing that the pyrolysis products of PCS exit as amorphous O_x-Si-C_y at low pyrolysis temperature, while a crystalline SiC phase emerges when the pyrolysis temperature exceeds 1500 ℃. Bulk (Zr, Hf, Nb, Ta, W)C-SiC_i ceramic was prepared by hot-pressing of precursor-derived ceramic powders obtained through pyrolysis at 1600 ℃. Mechanical properties of (Zr, Hf, Nb, Ta, W)C-SiC_i ceramic bulk were investigated, and composite ceramic bulks toughened by commercial silicon carbide nanopowders or silicon carbide whiskers were also prepared for comparison. Compared with (Zr, Hf, Nb, Ta, W)C ceramic, all composite ceramic bulks exhibit enhanced flexural strength and toughness. Notably, the in-situ generated SiC_i via precursor-derived method shows the most significant toughening effect. Flexural strength and fracture toughness of (Zr, Hf, Nb, Ta, W)C-SiC_i ceramic are (698±9) MPa and (7.9±0.6) MPa·m^1/2, respectively, representing improvements of 17.71% and 41.07% compared to that of (Zr, Hf, Nb, Ta, W)C ceramic bulk. Taking all above data into comprehensive account, the improvement is mainly due to the small grain size and uniform distribution of SiC in the composite ceramics prepared via precursor-derived method, which enhance energy consumption and hinder crack propagation under external stress.

Development of novel artificial synaptic devices, which make up the majority of neural networks, has emerged as a pivotal path to hardware realization of neuromorphic computing. An electrochemical ion synapse, also known as a three-terminal synaptic device based on electrochemical transistors, is a device that may efficiently use ions in the electrolyte layer to modify channel conductivity. By electrochemical doping and recovering ions in channel materials exhibiting redox activity, this device mimics biological synaptic properties. The advantages of the electrochemical ion synapse, which uses proton (H⁺) as the doping particle, are lower energy consumption, faster operation, and a longer cycle life among the ions that alter the channel material's conductance. This article reviews the recent research progress on proton-regulated electrochemical ion synapses, summarizes the material systems used for the channel layer and electrolyte layer of proton-regulated electrochemical ion synapses, analyzes the challenges faced by proton-regulated electrochemical ion synapses, and points out directions on their future development.

Inorganic nanoparticles have demonstrated significant applications in biomedicine field, whose biomedical functions and physicochemical properties are greatly influenced by their size and morphology. However, it still remains challenging to achieve high batch-to-batch reproducibility in the synthesis of inorganic nanoparticles with traditional batch synthesis methods. Meanwhile, microfluidic technology offers an advanced strategy that provides high controllability and repeatability for the synthesis of inorganic nanoparticles. Additionally, it facilitates rapid mass and heat transfer, while offering the advantages of small reaction volumes and low energy consumption, rendering it an ideal approach for the synthesis of inorganic nano-biomaterials. This article reviews the research and application progress of microfluidic technology in preparation of inorganic nano-biomaterials. Firstly, flow regimes and principles of mixing in the microfluidic devices are introduced. Subsequently, structural features and fluid mixing efficiency of five widely studied and applied microfluidic devices are presented. Importantly, applications of these microfluidic devices in synthesis and surface modification of inorganic nanoparticles are comprehensively summarized. Finally, this article briefly outlines challenges and potential opportunities for future developments in microfluidic-based synthesis and application of inorganic nano-biomaterials.

Ag₂Se-based thermoelectric films and devices have become a popular research topic in the field of wearable thermoelectric energy conversion due to their narrow bandgap semiconductor properties, which exhibit good thermoelectric properties at room temperature. These films are typically constructed by stacking nanoparticles, and the dimensions of nanomaterials significantly impact the thermoelectric transport properties of the network. In this study, Ag₂Se nanomaterials with different dimensions were prepared by solvothermal and template methods, and flexible Ag₂Se thermoelectric films were constructed on polyimide substrates using Ag₂Se nanomaterials with different dimensions by spraying process combined with high-temperature post processing. The effects of the dimensionality of Ag₂Se nanomaterials on the microstructures and thermoelectric properties of the films were then systematically investigated. Zero dimensional Ag₂Se nanoparticles exhibited superior conductive networks and thermoelectric properties in comparison to one dimensional nanowire structures. Furthermore, the room temperature power factor of the films reached 199.6 μW·m^-1·K^-2, and the power factor was 257.9 μW·m^-1·K^-2 at the temperature of 375 K, which indicated the good thermoelectric properties of the films. Additionally a device was designed and integrated based on the Ag₂Se films, with four thermoelectric arms and excellent performance. The device exhibited good mechanical flexibility and output performance with internal resistance increased by only 8.2% after 1000 bending cycles (bending radius: 20 mm), and the device displayed an open-circuit voltage of 9.1 mV and a max output power of 43.7 nW at a temperature difference of 30 K. This study presents a novel approach for the preparation of flexible Ag₂Se-based thermoelectric thin-film materials and devices.

The fabrication of large-area, high-efficiency perovskite solar cell module (PSM) represents a pivotal stage in the industrialization of perovskite solar cells (PSCs). Leveraging volatile solvents within perovskite precursors is a streamlined approach which offers distinct advantages in the industrialization trajectory of PSCs, but often exhibits accelerated crystallization kinetics, diminutive grain dimensions and elevated defect densities within the films, consequently compromising device efficiency and stability. This study devised a volatile solvent system comprising methylamine/acetonitrile (MA/ACN) for the production of MAPbI₃ perovskite solar cells/module. Incorporation of an optimal quantity of PbCl₂ into the perovskite precursor solution served to retard crystallization kinetics and passivate grain boundary imperfections. Notably, small-area device fabricated via this methodology demonstrated a peak photovoltaic conversion efficiency (PCE) of 21.21%, alongside enhanced operational stability. Furthermore, PSM engineered through this approach achieved a PCE of 18.89%. This study presents a novel paradigm for advancing the large-scale industrial manufacturing of PSCs.

Piezoelectric multilayer actuators feature large displacement generation at a relatively low driving voltage and are widely used in various fields. As the most commonly used material in multilayer actuators, soft lead zirconate titanate (PZT) ceramics have higher dielectric constant and loss, which often lead to higher power consumption and heat generation that in turn affect fatigue characteristics and stability of piezoelectric multilayer actuators. In this work, Mn-doped (in mole fraction) Pb(Sb_1/2Nb_1/2)_0.02Zr_0.51Ti_0.47O₃-0.6%MnCO₃ (PSN-PZT) hard ceramic was selected as base material in order to prepare piezoelectric ceramics that have low heat generation and are suitable for the application of piezoelectric multilayer actuator. Certain amount of Li₂CO₃ was doped as sintering aid for lowering sintering temperature of ceramics, and above-Curie-temperature polarization was utilized to enhance electric properties of ceramics. Eventually, multilayer actuator composed of this material was fabricated via tape-casting process and compared with Pb(Mg_1/3Nb_2/3)_0.25(Ti_0.48Zr_0.52)_0.75O₃ (PMN-PZT) actuator prepared with the same parameters. The results indicated that the sintering temperature of PSN-PZT ceramic was decreased to 1050 ℃ due to Li₂CO₃ sintering aid, which introduced liquid sintering during the sintering process. PSN-PZT ceramics poled above the Curie temperature obtained optimal electric performance with 0.1% (in mass) Li₂CO₃ doping, and the piezoelectric coefficient (d₃₃) and unipolar strain at 2 kV/mm reached 388 pC/N and 0.13%, respectively. The results of temperature rise and strain degradation of both multilayer actuators indicated that the temperature rise of hard PSN-PZT actuator was about 20 ℃ lower than that of PMN-PZT actuator under 200 Hz and the strain decreased by 6% after 5×10⁶ cycles. It indicates that PSN-PZT ceramics with Li₂CO₃ doping for lowering sintering temperature have some advantages in heat generation and fatigue characteristic while having descent piezoelectric properties, which endows it an important potential application in high-power, high-frequency and other demanding working conditions.

Material property differences among components of solid oxide fuel cell (SOFC) lead to excessive stresses during cell fabrication and operation, among which functional gradient material electrodes have attracted attention for their ability to reduce residual and thermal stresses in SOFC. But so far, there is rare study on SOFC with functional gradient anode using numerical simulation of thermal stress. In this study, a multi-physics field coupling model of SOFC with complete structure was established by COMSOL Multiphysics 6.0. Based on multi-physics field coupling model and numerical simulation of the residual stresses and thermal stresses in SOFC, four different distribution curves were employed to characterize the component distribution of anode materials. The results show that the tensile stress of anode can be significantly reduced by using functional gradient material during fabrication at different temperatures, especially at room temperature. Compared with non-gradient distribution, the maximum tensile stress of the anode is reduced by 47.69% before reduction and 35.74% after reduction by using quadratic curve distribution. During the operation process, the heat generated by the electrochemical reaction and the convective heat transfer of gas leads to the temperature difference between inlet and outlet, resulting in significant stress concentration at inlet and outlet of the metal frame as well as at contact surface between rib and electrode. Functional gradient materials can significantly reduce the maximum stress on the anode, metal frame and electrolyte, which is particularly obvious when using quadratic curve distribution. Therefore, this research has potential theoretical significance and engineering value for designing and fabricating SOFCs.

Compared with antibiotics and other drugs with poor functionalities and risk to induce bacterial resistance, inorganic functional nanomaterials with catalytic activity occupy an increasingly important position in the treatment of pathogenic infections by advantages of high response to the infected microenvironment (e.g. weak acid, high H₂O₂ concentration) or external physical stimuli (e.g. laser, ultrasound) and broad-spectrum sterilization. However, the acidic infection microenvironment is weak and unstable, and light or sound signals with high power density will cause damage to human cells. In addition, antimicrobial applications of alternative magnetic field (AMF), a non-invasive signal type with high tissue penetration, convenience to be remotely controlled, and effective magnetoelectric catalysis based on AMF have not been reported. In this study, an AMF-responsive nanocatalytic strategy based on the magnetostrictive-piezoelectric catalytic effect was applied to antibacterial research, and the surface of CoFe₂O₄-BiFeO₃ magnetoelectric nanoparticles (BCFO) was modified with the nitrogen-containing group L-arginine (LA) to achieve a magneto-electric responsive controlled release of powerful bactericide reactive nitrogen species (RNS). In AMF, BCFO simultaneously generates reactive oxygen species (ROS) hydroxyl radical (·OH) and superoxide anion (·O₂^-). The former reacts with LA to release nitric oxide (NO), and the latter combines with NO to produce peroxynitrite (ONOO^-), a typical RNS. As a highly active nitrification and oxidation agent, ONOO^- could exhibit stronger antibacterial activity than ROS under biofriendly AMF. Successful production of ONOO^- and achievement of stronger bactericidal efficiency were validated in this study. This work not only applies magnetoelectric nanocatalysis for antibacterial purposes, but also significantly improves the antibacterial ability through the conversion of ROS to RNS.

The research of sodium-ion batteries (SIBs) is of great significance for development of new energy and energy storage methods. As cathode material, P2-type layered oxide material Na_2/3Ni_1/3Mn_2/3O₂ has attracted wide attention due to its excellent capacity and high working voltage. However, it suffers from undesired P2-O2 phase transition, which leads to a drastic change in volume and rapid capacity decay. Here, a P2-Na_0.67Ni_0.18Cu_0.10Mg_0.05Mn_0.67O₂ (NCMM-10-05) cathode was synthesized through solid-state method with synergetic substitution of Cu and Mg. The results indicated that the incorporation of Cu and Mg suppressed irreversible P2-O2 phase transition when charging to high voltage and initialized OP4 phase formation, which improved reversible stability of structure. Thus the as-obtained material exhibited excellent electrochemical performance, which delivered an initial discharge capacity of 113 mAh·g^-1 in the voltage range of 2.00-4.35 V (vs. Na⁺/Na), a reversible capacity of 64.1 mAh·g^-1 at 8C (1C=100 mA·g^-1), and a capacity retention of 88.9% after 200 cycles at 1C. The effect of Cu and Mg synergetic substitution on the structure and electrochemical properties of P2-type layered oxides was explored, and the specific roles played by Cu and Mg in the structural evolution were further investigated by in situ X-ray diffraction (XRD) analysis and density functional theory (DFT) calculations. This work provides a new insight into the rational design of highly stable cathode materials with rapid Na⁺ transport capability for SIBs.

Metal phosphides have been studied as prospective anode materials for sodium-ion batteries (SIBs) due to their higher specific capacity compared to other anode materials. However, rapid capacity decay and limited cycle life caused by volume expansion and low electrical conductivity of phosphides in SIBs remain still unsolved. To address these issues, GeP₃ was first prepared by high-energy ball milling, and then Ketjen black (KB) was introduced to synthesize composite GeP₃/KB anode materials under controlled milling speed and time by a secondary ball milling process. During the ball milling process, GeP₃ and KB form strong chemical bonds, resulting in a closely bonded composite. Consequently, the GeP₃/KB anodes was demonstrated excellent sodium storage performance, achieving a high reversible capacity of 933.41 mAh·g^-1 at a current density of 0.05 A·g^-1 for a special formula of GeP₃/KB-600-40 sample prepared at ball milling speed of 600 r/min for 40 h. Even at a high current density of 2 A·g^-1 over 200 cycles, the capacity remains 314.52 mAh·g^-1 with a retention rate of 66.6%. In conclusion, this work successfully prepares GeP₃/KB anode-carbon composite for electrodes by high-energy ball milling, which can restrict electrode volume expansion, enhance capacity, and improve cycle stability of SIBs.

With upgrading of communication technology and driving of 5G communication applications, the explosive number of filters required by various smart devices promoted prosperity of the filter market. However, the demanded performance also becomes increasingly stringent, including broad bandwidth, high frequency, high power capacity, miniaturization, integration, and low cost, in both academia and industry. To meet these strict requirements, the thin film bulk acoustic resonator (FBAR) filters have emerged as one of the most promising types of filters with commercial success. But currently they are still facing difficulties such as insufficient performance, complex fabrication process, relatively higher cost, and technological constraints. This paper reviews the relevant issues and key technologies in FBAR filters in three aspects: theoretical research on devices and structural optimization, preparation and optimization of high-performance piezoelectric materials, and development of novel processes and technological integration. The purpose of this paper is to delineate the trajectory of technological advancements and iterations in FBAR filters for scholars in the research field, with the expectation of providing several considerations for future research directions and pathways.

With the rapid development of new aerospace vehicles, there are increasing demands for higher structural reliability and wideband microwave stealth requirements for the components operating under high-temperature condition. SiBCN based metastable ceramics exhibit good resistance to high temperature, thermal shock, ablation, long-term oxidation, and creep, showcasing great potential in the field of high-temperature structural microwave absorption. However, their ability to absorb electromagnetic waves is limited by low dielectric loss. In this study, the SiBCN-rGO ceramic fibers with good mechanical and microwave-absorbing properties were prepared using the wet spinning technology. Results showed that the as-prepared SiBCN-rGO ceramic fibers possessed porous structure, with porosity increasing with the increase of reduced graphene oxide (rGO) content. Additionally, both high rGO content and high fiber specific surface area promoted the crystallization of SiC within the amorphous matrix. The introduction of rGO significantly enhanced the tensile properties of the resulting ceramic fibers. As the mass fraction of rGO increased from 0 to 4%, the fibers’ elongation at break increased from 8.05% to 18.05%, and the tensile strength increased from 1.62 cN/dtex (0.324 GPa) to 2.32 cN/dtex (0.464 GPa). The increase of rGO content also reduced the electrical resistivity of the ceramic fibers. Moreover, as the rGO mass fraction increased from 0 to 4%, both the real and imaginary parts of the fibers’ dielectric constant decreased, while the loss tangent gradually increased. The SiBCN-rGO ceramic fibers with those containing 6% (mass fraction) rGO exhibited excellent wave-absorption performance, showing the minimum reflection coefficient of -50.90 dB at 9.20 GHz and an effective absorption bandwidth of 2.3 GHz, indicating promising applications in wave-absorbing ceramic matrix composites.

Control and removal of volatile organic compounds (VOCs) have always been critical issues in the environmental field. Catalytic oxidation has emerged as one of the most promising technologies for VOCs removal due to its low operational temperature, high efficiency, and non-toxic by-products. Perovskite oxides (ABO₃) are recognized as efficient and stable catalysts for the catalytic oxidation of VOCs. To enhance the catalytic efficiency of perovskite-based catalysts, it is necessary to systematically analyze and optimize the design of perovskite oxides to meet the specific requirements for the removal of different VOCs. This paper comprehensively reviews recent advances in the catalytic oxidation of VOCs using perovskite oxides. Firstly, various design strategies for perovskite oxides in the catalytic oxidation of VOCs, including morphology control, A-site and B-site substitution, defect engineering, and supported perovskite catalysts, are introduced, giving a close link between the catalytic performance of perovskite oxides and their material composition, morphology, surface properties (oxygen species, defects), and intrinsic properties (oxygen vacancy concentration, lattice structure). The reaction mechanisms and degradation pathways involved in the catalytic oxidation of VOCs are analyzed, and the prospects and challenges in the rational design of perovskite oxide catalysts and the exploration of reaction mechanisms are outlined.

Currently, the carbothermal reduction-nitridation (CRN) process is the predominant method for preparing aluminum nitride (AlN) powder. Although AlN powder prepared by CRN process exhibits high purity and excellent sintering activity, it also presents challenges such as the necessity for high reaction temperatures and difficulties in achieving uniform mixing of its raw materials. This study presents a comprehensive investigation into preparation process of AlN nanopowders using a combination of hydrothermal synthesis and CRN. In the hydrothermal reaction, a homogeneous composite precursor consisting of carbon and boehmite (γ-AlOOH) is synthesized at 200 ℃ using aluminum nitrate as the aluminum source, sucrose as the carbon source, and urea as the precipitant. During the hydrothermal process, the precursor develops a core-shell structure, with boehmite tightly coated with carbon (γ-AlOOH@C) due to electrostatic attraction. Compared with conventional precursor, the hydrothermal hybrid offers many advantages, such as ultrafine particles, uniform particle size distribution, good dispersion, high reactivity, and environmental friendliness. The carbon shell enhances thermodynamic stability of γ-Al₂O₃ compared to the corundum phase (α-Al₂O₃) by preventing the loss of the surface area in alumina. This stability enables γ-Al₂O₃ to maintain high reactivity during CRN process, which initiates at 1300 ℃, and concludes at 1400 ℃. The underlying mechanisms are substantiated through experiments and thermodynamic calculations. This research provides a robust theoretical and experimental foundation for the hydrothermal combined carbothermal preparation of non-oxide ceramic nanopowders.

Silicon-carbide-fiber-reinforced silicon-carbide-ceramic-based matrix (SiC/SiC) composites possess excellent properties such as low density, high strength and high temperature resistance, showing a potential application for structural components in the aerospace field, but their oxidation behavior remains largely unknown. In this study, Yb₂Si₂O₇ modified SiC/SiC (SiC/SiC-Yb₂Si₂O₇) mini-composites were prepared by introducing Yb₂Si₂O₇ as anti-oxidation phase into SiC fiber bundles via Sol-Gel and depositing SiC matrix by chemical vapor deposition (CVD). Influence of Yb₂Si₂O₇ on microstructure, mechanical property and oxidation behavior of SiC/SiC mini-composites was investigated. The results showed that after oxidation in air at 1200 and 1400 ℃ for 50 h, the tensile strength retentions of SiC/SiC mini-composites were 77% and 69%, respectively, and the fracture morphology exhibited flat. The Yb₂Si₂O₇ introduced by Sol-Gel partially distributed in layers, contributing to the toughening of the material. On the fracture surface, there was interlayer debonding, which extended energy dissipation mechanism of SiC/SiC mini-composites. Tensile strength of SiC/SiC-Yb₂Si₂O₇ mini-composites at room temperature was 484 MPa. After oxidation in air at 1200 and 1400 ℃ for 50 h, the tensile strengths decreased to 425 and 374 MPa, resulting in retention rates of 88% and 77%, respectively. It displayed typical non-brittle fracture characteristics. The interface oxygen content of SiC/SiC mini-composites at the fracture surface was higher than that of SiC/SiC-Yb₂Si₂O₇ mini-composites, indicating that introduction of Yb₂Si₂O₇ could alleviate oxygen diffusion towards the interface, and therefore improve the oxidation resistance of SiC/SiC-Yb₂Si₂O₇ mini-composites.

Hexagonal boron nitride (h-BN) ceramics have become exceptional materials for heat-resistant components in hypersonic vehicles, owing to their superior thermal stability and excellent dielectric properties. However, their densification during sintering still poses challenges for researchers, and their mechanical properties are rather unsatisfactory. In this study, SrAl₂Si₂O₈ (SAS), with low melting point and high strength, was introduced into the h-BN ceramics to facilitate the sintering and reinforce the strength and toughness. Then, BN-SAS ceramic composites were fabricated via hot press sintering using h-BN, SrCO₃, Al₂O₃, and SiO₂ as raw materials, and effects of sintering pressure on their microstructure, mechanical property, and thermal property were investigated. The thermal shock resistance of BN-SAS ceramic composites was evaluated. Results show that phases of as-preparedBN-SAS ceramic composites are h-BN and h-SrAl₂Si₂O₈. With the increase of sintering pressure, the composites’ densities increase, and the mechanical properties shew a rising trend followed by a slight decline. At a sintering pressure of 20 MPa, their bending strength and fracture toughness are (138±4) MPa and (1.84±0.05) MPa·m^1/2, respectively. Composites sintered at 10 MPa exhibit a low coefficient of thermal expansion, with an average of 2.96×10^-6 K^-1 in the temperature range from 200 to 1200 ℃. The BN-SAS ceramic composites prepared at 20 MPa display higher thermal conductivity from 12.42 to 28.42 W·m^-1·K^-1 within the temperature range from room temperature to 1000 ℃. Notably, BN-SAS composites exhibit remarkable thermal shock resistance, with residual bending strength peaking and subsequently declining sharply under a thermal shock temperature difference ranging from 600 to 1400 ℃. The maximum residual bending strength is recorded at a temperature difference of 800 ℃, with a residual strength retention rate of 101%. As the thermal shock temperature difference increase, the degree of oxidation on the ceramic surface and cracks due to thermal stress are also increased gradually.

Microwave dielectric ceramics are the key basic materials of 5G/6G communication technology, with particular emphasis on the materials that exhibit a high quality factor (Q×f), low dielectric constant (ε_r) and near-zero temperature coefficient of resonant frequency (τ_f). However, most low-ε_r materials tend to have a significantly negative τ_f value. This study provides a systematic overview of the classical ionic polarizability dilution mechanism and phase transition mechanism, along with the structural factors affecting τ_f, such as unit cell volume mechanism, oxygen polyhedron distortion, bond energy, bond ionicity, and bond valence. Subsequently, the anomalous changes in τ_f in the cubic normal and inverse garnet systems without phase transition are described in detail. The “Rattling” effect is introduced as a novel mechanism affecting the τ_f of microwave dielectric ceramics. Cations involved in “Rattling”, characterized by high coordination and weak chemical bonds, are the primary factors affecting the overall microwave dielectric polarization and loss of the material. This phenomenon results in an increase in ionic polarizability and ε_r, a forward shift in τ_f and a reduction in Q×f value, which has been verified and applied in many different material systems. Furthermore, the introduction of a weighted function for total ion polarization deviation serves to evaluate the impact of the entire molecule's “Rattling” and “Compressed” effects on ε_r. A novel concept of temperature coefficient of ionic polarizability (τ_αm) is also proposed, allowing for quantitative calculation. This simplifies the factors that affect the positive and negative of dielectric constant temperature coefficient (τ_ε), by relating it to ε_r, τ_αm and linear expansion coefficient α_L.

Ortho to para hydrogen conversion catalyst (O-P catalyst) is integral for large-scale hydrogen liquefaction projects. However, factors that influence catalyst performance remain preliminary and unclear. In the mean time, the mechanical strength of the O-P catalyst is crucial for its efficacy and longevity, yet most related research has paid sufficient attention to the catalytic activity. In this work, an iron-based O-P catalyst was synthesized using a straightforward precipitation method. And effects of catalyst activation method, drying temperature, particle size, concentration ratio, and doping element on catalytic activity and mechanical strength were studied. Furthermore, the catalytic performance and structural characterization of the prepared catalyst and commercial catalyst were compared. The prepared catalyst achieved a para hydrogen (p-H₂) content of 46.49% post-conversion at 77 K with a hydrogen flow rate of 1200 mL/min, surpassing the commercial catalyst by 2.9%. The maximum single particle crushing force of the prepared catalyst reached 4.75 N. Therefore, a preliminary mechanism for enhancing catalytic activity optimization was elucidated, offering valuable insights into ortho to para hydrogen conversion, and this study provides foundational data supporting the scaled production of domestic catalysts.

Piezoelectric materials, which serve as converters between mechanical energy and electric energy, are important functional materials. Recently, the technology for textured piezoelectric ceramics has become an important technical approach for developing the next generation of high-performance piezoelectric materials. By tailoring grain orientation, textured piezoelectric ceramics exhibit properties akin to single crystals, exhibiting enhanced piezoelectric and electromechanical properties, as well as improved thermal stability. Furthermore, as polycrystalline ceramics, textured ceramics inherit the advantages of traditional ceramic materials, including ease of fabrication, favorable mechanical properties, and suitability of special-shape and syntype. This paper provides a brief introduction to texturing technique, development of perovskite templates for textured ceramics, and research results related to lead titanate (PbTiO₃, PT) based textured piezoelectric ceramics. It systemizes the development and status of the piezoelectric textured ceramics while summarizing their technical advantages. Additionally, the existing scientific problems and future challenges of PT-based textured piezoelectric ceramics are analyzed, focusing on the suitability of templates and matrix via theoretical prediction, the relationship between microstructure and macroscopic properties of textured ceramics, and piezoelectric devices based on textured piezoelectric ceramics. By reviewing the PT-based textured piezoelectric ceramics, this paper aims to provide an in-depth introduction to texturing techniques and theories, seeks to enhance understanding of textured piezoelectric ceramics, and promotes the development of high- performance piezoelectric materials. This work is expected to benefit the breakthrough innovation and leap forward development of next generation high-end piezoelectric devices.

Pb(Zr,Ti)O₃-Pb(Zn_1/3Nb_2/3)O₃ (PZT-PZN) based ceramics, as important piezoelectric materials, have a wide range of applications in fields such as sensors and actuators, thus the optimization of their piezoelectric properties has been a hot research topic. This study investigated the effects of phase boundary engineering and domain engineering on (1-x)[0.8Pb(Zr_0.5Ti_0.5)O₃-0.2Pb(Zn_1/3Nb_2/3)O₃]-xBi(Zn_0.5Ti_0.5)O₃ ((1-x)(0.8PZT-0.2PZN)- xBZT) ceramic to obtain excellent piezoelectric properties. The crystal phase structure and microstructure of ceramic samples were characterized. The results showed that all samples had a pure perovskite structure, and the addition of BZT gradually increased the grain size. The addition of BZT caused a phase transition in ceramic samples from the morphotropic phase boundary (MPB) towards the tetragonal phase region, which is crucial for optimizing piezoelectric properties. By adjusting content of BZT and precisely controlling position of the phase boundary, the piezoelectric performance can be optimized. Domain structure is one of the key factors affecting piezoelectric performance. By using domain engineering techniques to optimize grain size and domain size, piezoelectric properties of ceramic samples have been significantly improved. Specifically, excellent piezoelectric properties (piezoelectric constant d₃₃=320 pC/N, electromechanical coupling factor k_p=0.44) were obtained simultaneously for x=0.08. Based on experimental results and theoretical analysis, influence mechanisms of phase boundary engineering and domain engineering on piezoelectric properties were explored. The study shows that addition of BZT not only promotes grain growth, but also optimizes the domain structure, enabling the polarization reversal process easier, thereby improving piezoelectric properties. These research results not only provide new ideas for the design of high-performance piezoelectric ceramics, but also lay a theoretical foundation for development of related electronic devices.

Fe@zeolite materials are widely applied in the production of ·OH by catalyzing Fenton-like reactions for degradation of recalcitrant organic pollutants due to their comprehensive sources, simple preparation and low environmental impact. However, the high cost of Fe@zeolite synthesis and the lack of Fe²⁺ regeneration strategy are serious issues that limit the application of Fe@zeolite as a Fenton-like catalyst in industrial-scale systems. In this study, the ash generated from activated sludge incineration treatment was utilized as raw material to selective recover Si, Al and Fe, preparing Fe²⁺-sodalite (FSD) material. Consequently, it was used as a Fenton-like catalyst to activate peroxyacetic acid (PAA) for the degradation of methylene blue (MB) in wastewater. Results indicated thatFSD was capable of effectively catalyzing PAA to generate various active oxygen species such as ·OH, ¹O₂ and R-O· in a wide pH range, thereby degrading MB through hydroxylation and sulfonation pathways. MB can be completely removed during 20 min under optimized conditions of 0.3 mmol/L PAA and 0.3 g/L FSD prepared with 0.5 mol/L Fe²⁺. In addition, the reductive S species in FSD can maintain its catalytical activity by enhancing Fe²⁺ regeneration, and the FSD/PAA system has been proven to be effective in the degradation of various organic pollutants under practical and complex environmental conditions.

Amorphous calcium carbonate (ACC) plays a crucial role in biomineralization which crystallization process has attracted significant attention. Magnesium ions (Mg²⁺) can effectively regulate the crystallization of ACC, but the mechanism by which it controls the transformation of ACC into monohydrocalcite (MHC, CaCO₃·H₂O) is not well understood. In this study, Mg²⁺ was used as an additive, and the transformation process from ACC to MHC was investigated in situ using an automatic potentiometric titration system. It was found that Mg²⁺ can enhance the stability of ACC and inhibit the formation of calcite and vaterite. During the transformation of ACC to MHC, partial dissolution firstly occurred, and the molar ratio of Mg/Ca in the solution increased with the consumption of Ca²⁺. Mg²⁺ further adsorbed onto the surface of ACC particles, inhibiting surface dissolution of ACC and promoting internal dissolution of ACC, resulting in the formation of hollow structures rich in Mg²⁺ and smaller-sized nanoparticles. Subsequently, MHC crystallized and grew through particle aggregation. These results elucidate the mechanism by which Mg²⁺ regulates the transformation of ACC into MHC through a non-classical crystallization pathway, enhancing an understanding of the biomineralization mechanism from ACC precursor.

Platinum (Pt)-based noble metal catalysts (PGMs) are the most widely used commercial catalysts, but they have the problems of high cost, low reserves, and susceptibility to small-molecule toxicity. Transition metal oxides (TMOs) are regarded as potential substitutes for PGMs because of their stability in oxidizing environments and excellent catalytic performance. In this study, comprehensive investigation into the influence of elastic strains on the adsorption energies of carbon (C), hydrogen (H) and oxygen (O) on TMOs was conducted. Based on density functional theory (DFT) calculations, these effects in both tetragonal structures (PtO₂, PdO₂) and hexagonal structures (ZnO, CdO), along with their respective transition metals were systematically explored. It was identified that the optimal adsorption sites on metal oxides pinpointed the top of oxygen or the top of metal atom, while face-centered cubic (FCC) and hexagonal close-packed (HCP) holes were preferred for the transition metals. Furthermore, under the influence of elastic strains, the results demonstrated significant disparities in the adsorption energies of H and O between oxides and transition metals. Despite these differences, the effect of elastic strains on the adsorption energies of C, H and O on TMOs mirrored those on transition metals: adsorption energies increased under compressive strains, indicating weaker adsorption, and decreased under tension strains, indicating stronger adsorption. This behavior was rationalized based on the d-band model for adsorption atop a metallic atom or the p-band model for adsorption atop an oxygen atom. Consequently, elastic strains present a promising avenue for tailoring the catalytic properties of TMOs.

SiC/SiC composites have emerged as essential thermal structure materials for development of hypersonic vehicles and high thrust-to-weight ratio aero-engines. Design and utilization of boron-containing ceramic precursors as impregnation agents for precursor infiltration and pyrolysis (PIP) to introduce self-healing components into matrix represent a key strategy for enhancing the antioxidant properties of SiC/SiC composites. Here, borane pyridine or borane triethylamine were utilized as boron sources and subsequently mixed with a solid polycarbosilane (PCS) xylene solution to prepare different boron-modified PCS solutions. These solutions were used as PIP impregnation agents to fabricate various boron-modified SiC/PyC (pyrolytic carbon)/SiC composites. The physicochemical properties of boron-modified PCS-derived ceramics, along with the physical and mechanical properties of SiC/PyC/SiC composites before and after matrix boron modification, were investigated. Results demonstrated that addition of appropriate amounts of borane pyridine and borane triethylamine as boron sources in solid PCS solutions effectively introduced boron as a heterogeneous element into the derived SiC ceramics. Compared to PCS, the boron-modified PCS solutions (BP-1 and BP-2) exhibited increased ceramic yields. The derived ceramics exhibited a semi-crystalline β-SiC structure, with boron element contents of 1.7% and 2.2% (in mass), respectively. In contrast to unmodified composite, the boron-modified SiC/SiC composites exhibited negligible changes in density, apparent porosity, and fracture toughness. However, the flexural modulus increased from 116 GPa to 132 GPa. Furthermore, the flexural strength of the modified composite using borane pyridine alone as boron source was 658 MPa, comparable to the unmodified composite's strength of 643 MPa, but with a reduced dispersion coefficient. All above data demonstrate that borane pyridine can be used as boron source for preparation of boron-modified SiC/SiC composites, providing valuable insights for developing high-performance SiC/SiC composite hot-end components.

Pb(Zr,Ti)O₃ (PZT) ceramics play a crucial role in fields such as national defense, healthcare, communication, and energy conversion due to their excellent piezoelectric, ferroelectric, and pyroelectric properties. However, the sintering temperature of PZT ceramics usually exceeds 1200 ℃, resulting in high energy consumption and a large amount of PbO volatilization. This volatilization disrupts the stoichiometric balance of PZT ceramics, thereby adversely affecting their electrical properties. Moreover, the rapid development of piezoelectric multilayer devices further requires PZT ceramics to be co-sintered with low-cost metal electrodes at low temperatures. To address these challenges, researchers have extensively investigated the low-temperature sintering of PZT piezoelectric ceramics, successfully reducing the sintering temperature of PZT ceramics to below 1000 ℃, which has attracted widespread attention. Starting from the structural characteristics and physical properties of PZT ceramics, this article reviews the current research status of low-temperature sintering technology in the field of PZT ceramics. It mainly introduces the current status of low-temperature sintering techniques, including spark plasma sintering, hot-pressing sintering, cold sintering, as well as the use of sintering aids such as forming solid solutions, liquid-phase sintering, and transient liquid-phase sintering. The influence of these sintering techniques on the microstructure and electrical properties of PZT piezoelectric ceramics is systematically summarized. The issue of electrical performance degradation caused by sintering aids and possible solutions are analyzed. At last, future development trends of low-temperature sintering technologies for PZT ceramic are explored.