Influence Of Surface Properties Of Supports On The Synthesis Of Supported Metal Catalysts And Their Catalytic Properties

The synthesis and catalytic properties of supported metal catalysts were influenced by the surface properties of supports,especially,when the size of the metal particles was very small,such as single metal atoms,metal clusters,etc,the synthesis and catalytic properties of the catalyst were more significantly affected.Chapter 1:Firstly,the catalysts were summarized,and then the influence of the surface properties of the supports on the synthesis and catalytic properties of supported metal catalysts was summarized.Finally,the research contents of this work were proposed.Chapter 2:We used mercaptoacetic acid as a bridge to connect the alumina and the silver precursor.First,we modified the alumina with a small amount of mercaptoacetic acid in the aqueous phase,and then adsorbed the silver ions in silver nitrate with a mercapto group of mercaptoacetic acid to uniformly support the silver on the alumina.After the reduction,the loading was 15 wt%,silver seed crystals with a very small average particle size were synthesized.By a seed growth method,Ag/Al2O3 catalyst having a loading capacity of 30 wt%and an average particle size of less than 10 nm was synthesized.We recognized the importance of organic ligands on the surface of the supports for the synthesis of catalysts during the synthesis process.Using the catalyst for the epoxidation of ethylene,we observed that the nature of the alumina had a great influence on the selectivity of the reaction.Chapter 3:Organic ligands on the support surface were very important for the synthesis of catalysts.Combining with the synthesis of Pd1/TiO2 catalyst and the catalytic hydrogenation of styrene,we performed the performance and mechanism of the catalytic hydrogenation of benzaldehyde by Pdi/TiO2.For further study,the catalyst had excellent catalytic properties for the catalytic hydrogenation of benzaldehyde.During the catalytic process,we discovered the solvent effect and quantum tunneling effect.The catalytic mechanism was the solvent-assisted proton tunneling.Meanwhile,the catalyst’s catalytic universality was excellent.Catalyzing at the Pd-O interface rather than a single Pd atom,we further realized that the organic ligands on the surface of the supports not only played an important role in the synthesis of catalysts,but also played an important role in the catalytic process.Chapter 4:Summarizing the works of this thesis,we put forward further research ideas and prospects.