Modulating the Electronic Metal-Support Interactions to Anti-Leaching Pt Single Atoms for Efficient Hydrosilylation

Modulating the electronic metal-support interaction (EMSI) of the single-atomic sites against leaching via microenvironment regulation is critical to achieving high activity and stability but remains challenging. Herein, this work selectively confines Pt single atoms on CoFe layered double hydroxide (LDH) by three oxygen atoms around cation vacancy (Pt1/LDHV) or one oxygen atom at the regular surface (Pt1/LDH) via cation vacancy engineering. By characterizing the structural evolution of the obtained catalysts before and after vacancy construction and single-atom anchoring, this work demonstrates how the microenvironments modulate the EMSI and the catalytic performance. Theoretical simulations further reveal a significantly enhanced EMSI effect by the three-coordinated Pt1 atoms on cation vacancies in Pt1/LDHV, which endows a more prominent anti-leaching feature than the one-coordinated ones on the regular surface. As a result, the Pt1/LDHV catalyst shows exceptional performance in anti-Markovnikov alkene hydrosilylation, with a turnover frequency of 1.3 x 105 h-1. More importantly, the enhanced EMSI of Pt1/LDHV effectively prevented the leaching of Pt atom from the catalyst surface and can be recycled at least ten times with only a 3.4% loss of catalytic efficiency with minimal Pt leaching, and reach a high turnover number of 1.0 x 106. Pt single-atom catalysts (SACs) with different microenvironments have been implemented by introducing cation vacancies into CoFe-Layered double hydroxide (LDH). Compared with Pt anchored on the surface of CoFe-LDH, Pt anchored on cobalt vacancies exhibits stronger electronic metal-support interaction between the Pt atoms and the oxide atoms of CoFe-LDH, which result in a superior activity and stability in the hydrosilylation.image