Thermoelectric materials are functional materials that can realize the direct conversion between heat and electricity, which have great prospects in the field of green refrigeration and waste heat recovery. To date, researches on thermoelectric materials mainly focus on semiconducting inorganic materials and conductive polymers. Although great progress has been made regarding material design and performance improvement, it is still of great significance to explore and expand thermoelectric candidates for potential application. Metal-organic frameworks (MOFs) are porous extended solids formed by coordination bonds between organic ligands and metal ions or metal clusters. They are promising candidates in the field of thermoelectrics due to their unique porous structure as well as tunable composition and structure, which could meet the requirement of "electron crystal-phonon glass". In this work, conductive polymer, poly(3, 4-vinyl dioxythiophene) (PEDOT) was in-situ polymerized in Zr-based MOFs UiO-67 through “conductive guest-promoted transport” approach. The confined effects originated from porous structures of MOFs on molecular chains of PEDOT effectively improve electrical conductivity of the composites. As a result, the prepared composites exhibit an electrical conductivity up to 5.96×10⁻³ S·cm⁻¹ at room temperature, which is one order of magnitude higher than the corresponding PEDOT. Correspondingly, their power factor (PF) is up to 3.67×10⁻² nW·m⁻¹·K⁻² at room temperature. In conclusion, this work uses ordered porous structures of MOFs as reaction platform and constructs conductive polymer/MOFs conductive materials by facile in-situ polymerization methods, providing a reference for further development of MOFs-based thermoelectric materials.

Cu/Mg-MOF-74 has several advantages, such as high specific surface area, adjustable microporous structure, alkali metal active site, excellent CO₂ adsorption, and good photocatalytic activity. However, how the molar ratio of Cu/Mg (Cu/Mg ratio) affects its CO₂ adsorption selectivity in a simulated flue gas is still unclear. Here, a synthesized Cu/Mg-MOF-74, with series of Cu/Mg ratios, using the solvothermal method was analyzed about its CO₂ photocatalytic performance, CO₂ and N₂ uptake, and pore structure. The CO₂ adsorption selectivity was calculated to reveal the effect of Cu/Mg ratio on CO₂ and N₂ uptake and selectivity. The results indicate that the photocatalytic activity of Cu/Mg-MOF-74 for CO₂ reduction to CO and H₂ initially increases and then decreases with Cu/Mg ratio decreasing. At the Cu/Mg ratio of 0.6/0.4, the yield of CO and H₂ by photocatalytic reduction is the highest, showing up to 10.65 and 5.41 μmol·h⁻¹·g_cat⁻¹ (1 MPa, 150 ℃), respectively. Furthermore, CO₂ and N₂ uptakes of Cu/Mg-MOF-74 increase as the Cu/Mg ratio decreases, and the increase in CO₂ uptake is more pronounced. At the Cu/Mg ratio of 0.1/0.9, the CO₂ and N₂ uptakes are the largest, reaching 9.21 and 1.49 mmol·g⁻¹ (273.15 K, 100 kPa), respectively. Their area and volume of micropore (d₁ ≥ 0.7 nm) and ultramicropore (d₂ < 0.7 nm) increase as the Cu/Mg ratio decreases. At the Cu/Mg ratio of 0.22/0.78, the area and volume of micropores and ultramicropores are larger than those of Mg-MOF-74. The selectivity of Cu/Mg-MOF-74 increases correspondingly with Cu/Mg ratio decreasing and CO₂ concentration increasing. CO₂ adsorption on Cu/Mg-MOF-74 is a combination process of pore-filling and Mg²⁺ chemical adsorption in which the micropore volume is the key factor affecting its adsorption performance. All above data demonstrate that modulating the Cu/Mg ratio can promisingly regulate the pore structure of Cu/Mg-MOF-74, CO₂ uptake, and selectivity.

The all-inorganic CsPbX₃ (X=Cl, Br, I) perovskite nanocrystals have been widely applied in optoelectronic devices due to their excellent optoelectronic properties. However, their poor stability remains one of the main factors restricting their commercial development. This research focuses on improving the stability and solid-state luminescence performance of CsPbBr₃ nanocrystals. The porous MIL-53 (Al) metal-organic frameworks (MOFs) with outstanding hydrophobic properties was chosen as the encapsulation matrix. CsPbBr₃ nanocrystals were grown in situ within the MIL-53 (Al) channels by using a thermal injection process to successfully synthesize CsPbBr₃@MIL-53 nanocomposite phosphors with outstanding solid-state luminescence performance and high stability. MIL-53 chelates with CsPbBr₃ nanocrystals through benzene rings and organic ligands, firmly anchoring nanocrystals in the pores. This not only protects the CsPbBr₃ nanocrystals from external environmental influences but also effectively prevents aggregation between nanocrystals, thereby avoiding quenching of solid-state fluorescence. Additionally, the COO^- functional groups in MIL-53 bind with the unpaired Pb²⁺ on the surface of CsPbBr₃ nanocrystals, passivating the surface defects and suppressing non-radiative carrier recombination. Furthermore, the contained benzene rings and organic long chains endow the nanocomposite phosphors with excellent hydrophobic properties. The synergistic effect of these factors significantly enhances the optical performance and water stability of CsPbBr₃@MIL-53 nanocomposite phosphors. As a result, photoluminescence quantum yield (PLQY) of CsPbBr₃@MIL-53 nanocomposite phosphors reaches 75.4%, which is 2.3 times of that of solid-state CsPbBr₃ nanocrystal powders (33.2%). Even after being completely immersed in water for 10 h, its fluorescence intensity can still maintain 75.6% of the initial value. Finally, the green-emitting CsPbBr₃@MIL-53 nanocomposite phosphors were applied to white LED devices, achieving a wide-color-gamut coverage area of 126% NTSC and 85% Rec. 2020, which demonstrates its application prospects in wide-color-gamut display devices.

Volatile organic compounds (VOCs) pose significant risks to environmental quality and human health. To enhance adsorption performance of adsorbents for VOCs, further improvement of the unsaturated metal centers becomes a key factor based on the principle that metal ions can be replaced in metal organic frameworks (MOFs). Here, a one-step solvothermal synthesis system was utilized to dope abundant, cost-effective, and environment friendly Al³⁺ ions into MIL-101(Cr) for preparing Al-MIL-101(Cr). Morphologies and structures of MIL-101(Cr) and Al-MIL-101(Cr) samples, alongside the static adsorption performance for toluene, n-hexane, oil and p-xylene, were analyzed. Static adsorption capacities of toluene, n-hexane, oil, and p-xylene of MIL-101(Cr) were 0.676, 0.621, 0.451 and 0.812 g·g^-1, respectively. When Al³⁺ doping amount reached 0.75 mmol, Al-0.75-MIL-101(Cr) displayed maximum VOCs adsorption capacities (0.911 g·g^-1 for toluene, 0.755 g·g^-1 for n-hexane, 0.713 g·g^-1 for oil, and 0.875 g·g^-1 for p-xylene). The dynamic toluene adsorption behavior was assessed through single-component breakthrough curves. Both dynamic and static adsorption results demonstrate that Al-MIL-101(Cr) possesses excellent VOCs removal capabilities, which are attributed to the extensive specific surface area and augmented unsaturated metal sites.

Lithium-ion batteries (LIBs) are widely applied to various portable electronic devices and new energy vehicles. However, the traditional graphite anode with low theoretical capacity (372 mAh/g) is unable to meet the need of the rapid development of economy and society. Herein, a zinc-based metallic organic framework (ZIF-8) derived three-dimensional network carbon coated silicon (Si@NC) composite was designed for lithium-ion battery. Firstly, the surface of nano-silicon was chemical modified; secondly, small size ZIF-8 was in situ grown on the silicon surface to form Si@ZIF-8; finally, the three-dimensional network Si@NC composite was obtained by carbonization. Results show that the three-dimensional network porous structure of the Si@NC composite not only limits the volume expansion of silicon, but greatly improves the conductivity of the materials, exhibiting excellent cycle stability and outstanding rate performance. As a result, a discharge specific capacity of 760 mAh/g is maintained at a high current density of 5 A/g. Using commercial material as cathode and Si@NC as anode, the assembled full LIBs demonstrate a capacity retention of 60.4% at 0.4C (1C =160 mA/g) for 50 cycles. These results indicate that the as-synthesized three-dimensional network porous structure of Si@NC composite has a potential practical application for LIBs.

Room temperature ionic liquid shows wide electrochemical windows and good environmental stability, which is expected as an ideal electrolyte for electrochromic devices. However, the small crystal spacing of traditional electrochromic materials limits the diffusion of large ions in ionic liquid. Repeated deintercalation/ intercalation of large ions could also destroy the structure of traditional electrochromic materials, resulting in performance degradation. Metal-organic frameworks (MOFs) are topologically porous materials with a large intrinsic nano to microporous structure in crystalline, which are expected to provide channels for transporting large-sized ions in ionic liquids. In present work, triphenylene-based MOFs Cu₃(HHTP)₂ films were prepared on the surface of the conductive glass. Electrochemical and electrochromic behavior of Cu₃(HHTP)₂ films were studied in traditional propylene carbonate (PC)-based electrolyte and ionic liquid-based electrolytes. The results show that, compared with the traditional LiClO₄/PC or NaClO₄/PC electrolyte, Cu₃(HHTP)₂ film displays low contact resistance and high ion diffusion efficiency in the ionic liquid [EMIm]BF₄ electrolyte. Switch speed of the electrochromic electrode is significantly improved with coloring time being reduced from 10.3 s to 8.0 s, and bleaching time being reduced from 23.6 s to 5.2 s. Meanwhile, Cu₃(HHTP)₂/[EMIm]BF₄ electrochromic system also shows a larger light modulation range and coloring efficiency. This work demonstrates the potential of MOFs/ionic liquid electrochemical system in the field of electrochromic device.

Broad application of nuclear energy has resulted in the release of radionuclides such as uranium [U(VI)], into the environment, and its potential toxic and irreversible effects on the environment are among the paramount issues in nuclear energy use. Graphite carbon nitride (g-C₃N₄) is a kind of non-metallic material with the triazine structure. In recent years, the reduction of U(VI) to insoluble U(IV) by g-C₃N₄ photocatalysis has become a major research focus on the area of radioactive pollutants. In this work, a metal-organic framework (MOF) material containing cobalt metal was used as a self-sacrificial template. Through simple thermal copolymerization, the Co-N_x coordination was successfully incorporated into g-C₃N₄ to synthesize the CoN_x/g-C₃N₄ photocatalyst. The effects of the morphology, structure, and photoelectric properties of CoN_x/g-C₃N₄ on the photocatalytic reduction of U(VI) were investigated using macroscopic batch experiments. The results showed that the introduction of Co effectively broadened the absorption range of g-C₃N₄ to visible light, inhibited recombination of the photogenerated electrons and holes, and facilitated the reduction of U(VI). Under irradiation in visible light for 45 min, pH 5.0 and solid-liquid ratio of 1.0 g/L, the photocatalytic reduction of a standard 50 mg/L U(VI) solution reached 100% by CoN_x/g-C₃N₄(w(Co-MOFs) : w(g-C₃N₄)=1 : 1). Furthermore, the photocatalytic mechanism of CoN_x/g-C₃N₄ was investigated through capture experiments. In summary, the CoN_x/g-C₃N₄ composite exhibits excellent optical performance, has simple operation, is eco-friendly, and has a significant photocatalytic effect on U(VI) in radioactive wastewater. This work also provides design strategy and technical reference for applying g-C₃N₄ materials to treat radioactive wastewater.

Luminescent materials have been widely used in confidential information protection and anticounterfeiting. Luminescent lead halide perovskite nanocrystals, which can be converted from the lead source through a two-step method, are attractive candidates for information encryption and decryption. Herein, the reversible conversion between the invisible lead-organic framework and the luminescent MAPbBr₃ nanocrystals is achieved, together with their further application on information storage by inkjet printing technology. The lead ions are embedded into the metal-organic frameworks through coordination with the 2-methylimidazole linkers. The inherent confined distribution of lead ions facilitates the in-situ growth of perovskite nanocrystals in the second step without the assistance of external bulky ligands. The recorded information was firstly encrypted by the lead organic frameworks, which is invisible under ambient and UV light. After reacting with methylammonium bromide, the perovskite nanocrystals are in-situ formed, and the information becomes readable under UV light. Using methylammonium bromide and water as the decryption and encryption reagents could also switch on/off the luminescence, therefore, realizing the confidential information storage.