Supported Palladium–Gold Alloy Catalysts for Efficient and Selective Hydrosilylation under Mild Conditions with Isolated Single Palladium Atoms in Alloy Nanoparticles as the Main Active Site

Supported Pd–Au alloy catalysts were developed for the highly efficient and selective hydrosilylation of α,β-unsaturated ketones and alkynes. The Pd/Au atomic ratio of the Pd–Au alloy and the supporting material affected the catalytic activity, and supported Pd–Au alloy nanoparticles with a low Pd/Au atomic ratio functioned as highly active heterogeneous catalysts under mild reaction conditions. Structural characterization of supported Pd–Au alloy catalysts by X-ray diffraction, X-ray absorption spectroscopy (XAS), and transmission electron microscopy revealed the formation of random Pd–Au alloy nanoparticles with a uniform size of around 3 nm on the support. Furthermore, XAS and X-ray photoelectron spectroscopy elucidated the charge transfer from Pd to Au and the formation of isolated single Pd atoms in random Pd–Au alloys with a low Pd/Au ratio, which enabled efficient hydrosilylation of a variety of substrates under mild reaction conditions.