Enhancing stability of mononuclear Pt atoms via chloride-to-bromide ligand exchange for hydrosilylation reaction

Single atom catalysts (SACs) offer high atom efficiency with highly selective reaction pathway. Various strategies have been developed to synthesize SACs, among which thermally stable metal centers are usually in high oxidation while they are susceptible to facile sintering in reduced state or under reducing conditions. One of the strategies developed very recently to achieve stable zero valent metal atoms is based on the selection of ligands with moderate coordination strength with the metal center. In this work, the crucial importance of ligand to the stability of single Pt 0 atoms is investigated. While HCl and diether have been found to be able to stabilize single Pt 0 atoms by forming Pt 1 @HCl adducts, HBr coordinated Pt single atom (Pt 1 @HBr) obtained by simply exchanging HCl with HBr shows increased thermal stability over the Pt 1 @HCl under H 2 atmosphere at elevated temperature, as evidenced by DRFITs of CO chemisorption and HRTEM. This work offers a facile approach to tune the stability of Pt single atoms while keeping the structure of active sites of single atom center to achieve excellent catalytic performance, using hydrosilylation in the demonstrative studies.