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 alpha,beta-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.