Generating highly dispersed and monosized metal nanoparticles on porous silica to prepare supported silica catalysts is challenging due to wettability issues. Better interaction between the metal precursor and the support has been considered as a potential strategy to avoid metal aggregation. Here we present a molecular approach where palladium diketone complex was incorporated on mesoporous silica (MCM-41) by a ligand exchange reaction. Subsequent thermal treatment under a controlled atmosphere provided MCM-41 nanospheres with integrated palladium nanoparticles. The effect of the gaseous atmosphere on the composition, morphology, and catalytic activity was investigated. When used in multifunctional catalysis, the catalyst pyrolyzed in the air [Pd@MCM-41a] exhibited the highest activity and enhanced selectivity in the dehydrogenation of sodium borohydride (NaBH4), methanolysis of ammonia borane (NH3BH3), and reduction of 4-nitrophenol. The activation energies for the dehydrogenation/methanolysis of NaBH4 and NH3BH3 were measured to be 14.35kJ/mol and 34.31kJ/mol, respectively. The reduction of 4-nitrophenol has a rate constant of 7 × 10-3 s-1, which surpasses that of commercial silica, carbon, and alumina-based palladium catalysts. We attribute the outstanding catalytic activity of Pd@MCM-41a to the uniformly distributed ultra-small palladium particles.

Multifunctional catalysts based on nanoscale palladium supported on mesoporous silica by a molecular approach

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.