How to design and fabricate highly efficient and stable Pt nano-catalyst is of important practical value and scientific significance for improving the C=O hydrogenation selectivity of cinnamaldehyde. In present study, a series of MgAl hydrotalcite (LDH) supports with various morphologies were synthesized by co-precipitation and hydrothermal methods. The supported Pt/LDH catalysts were prepared by incipient wet impregnation (IMP) method with LDH supports, and used for cinnamaldehyde selective hydrogenation reaction, and influences of LDH with different morphology for the catalyst activity were studied. The structure, morphology, surface physicochemical properties of these catalysts were characterized. The results show that the morphology of different supports exerts a significant influence on the structure and properties of Pt/LDH catalysts. Interaction between lamellae LDH nanosheet and active component Pt facilitates dispersing and stabilizing of Pt nanoparticles. Meanwhile, there are abundant alkaline sites and surface hydroxyl groups in the LDH support, which are beneficial to improve the catalytic hydrogenation activity and stability. Results of catalytic performance show that selectivity of cinnamon alcohol (CMO) and conversion of cinnamon aldehyde (CMA) at reaction temperature of 40 ℃, reaction pressure of 1 MPa, and reaction time of 120 min were 82.1% and 79.8%, respectively. After 5 rounds of cycle tests, the Pt/LDH catalyst still has excellent stability.

Solvent-free synthesis of zeolites has received extensive attention in recent years, because it is advantageous over conventional hydrothermal synthesis. Nevertheless, SAPO-34, a micropore zeolite, prepared by this method does not satisfy the catalytic lifetime requirements of the methanol-to-olefins (MTO) reaction. Herein, an improved solvent-free approach was developed to synthesize SAPO-34 catalysts with enhanced MTO reaction performance, in which acid-etched seed crystals were introduced to modulate the physico-chemical properties of the zeolite via crystallization kinetics regulation. The results indicated that the SAPO-34 samples prepared from seed-containing precursor gels show considerably higher crystallinity, larger surface area, but lower strong acid site density than the parent sample. In particular, the catalytic lifetime of the SAPO-34 catalyst prepared from activated seeds was remarkably prolonged to 480 min, which was significantly superior to that of the parent sample (40 min). The result confirmed the validity of the seeding approach for modifying the zeolite properties via the solvent-free synthesis and the potential of the approach in improving catalytic performance.

Hierarchically porous silica-aluminum is an important support material for metal-catalysts, because of its excellent properties. Herein, an efficient hydrothermal approach for the production of hierarchical aluminum- doped silica (Al-SiO₂) architectures was reported by employing aluminum nitrate as an aluminium source and TEOS as silicon source. Effects of the structure-oriented agent on the structure of Al-SiO₂ were investigated. Structural features of Al-SiO₂ were characterized by XRD, SEM and N₂-physisorption. The results showed that hierarchical Al-SiO₂ with "worm-like" porous of 30-40 nm can be synthesized by using TPAOH as the structure-oriented agent and hydrothermal treatment at 80 ℃. The cobalt catalysts were prepared by the wetness impregnation method. Compared with commercial SiO₂ supported cobalt catalysts, the Fischer-Tropsch synthesis performance of the catalyst Co/Al-SiO₂ is significantly enhanced, i.e., CO conversion nearly doubled, CH₄ selectivity reduced by 19.3wt%, C₂-C₄ selectivity reduced by 13.3wt%, and the selectivity of gasoline products (C₅-C₁₂) reached 53.3wt%.

The ammonia selective catalytic reduction (NH₃-SCR) technology is still necessary to further develop denitration catalytic materials which have good catalytic activity, high stability and environmental friendliness at relatively low temperature (<300 ℃). In this work, the Mn-Fe-O catalyst was prepared by oxalate co-precipitation method and modified with different contents of CeO₂ for low temperature NH₃-SCR of NO. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption, X-ray photoelectron spectroscopy (XPS), temperature programmed reduction or desorption (H₂-TPR, NH₃-TPD). The catalytic results show that as compared with pure Mn-Fe-O sample, Mn-Fe-O modified with suitable CeO₂ content shows much better performance for NH₃-SCR with 95% conversion of NO and a high N₂ selectivity at 80 ℃ under the same reaction conditions. CeO₂ modification increases the content of Fe ³⁺, Mn ³⁺ and Mn ⁴⁺, and the number of surface acid sites on the surface of Mn-Fe-O oxide, which contribute to the adsorption of NH₃ and the catalytic reaction. In addition, redox reactions among Fe ²⁺/Fe ³⁺, Mn ²⁺/Mn ³⁺/Mn ⁴⁺ and Ce ³⁺/Ce ⁴⁺ pairs improve the redox ability and stability of the catalyst.