General strategy for preparing metal single-atom site catalysts using Y-type molecular sieves

Nowadays, metal catalysts supported by molecular sieves have been widely used in industrial reactions such as hydrogenation/dehydrogenation, hydroalkylation, hydrocracking, and isomerization. However, in these catalysts, the diameter of metal nanoparticles (M-NPs) is usually 1.5-4 nm, and the phenomenon of metal nanoparticles blocking the micropores of the molecular sieve framework (<2 nm) or just attaching to the outer surface of the molecular sieve , Thereby reducing the catalytic activity of the catalyst. In theory, the metal single-atom site (M-ISAS) catalyst has the largest metal atom efficiency and the smallest volume occupancy. Based on this, molecular sieve-supported metal catalysts have recently made great progress in methane oxidation, nitrogen oxide reduction, water gas shift reaction, etc. However, NPs and ISAS are symbiotic under conventional wet impregnation (IWI) conditions, and NPs Usually does not have catalytic activity. Therefore, it is necessary to develop a new synthesis method to realize the uniform distribution of ISAS on the molecular sieve to obtain a high-performance molecular sieve supported metal catalyst.