Synergistic effect in bimetallic copper–silver (CuxAg) nanoparticles enhances silicon conversion in Rochow reaction

Abstract

The oleylamine thermal reduction process was employed to prepare bimetallic copper–silver (Cu_xAg (0 ≤ x ≤ 50)) nanoparticles, such as Cu, Cu₅₀Ag, Cu₂₀Ag, Cu₁₀Ag, Cu₅Ag, CuAg, CuAg₂, and Ag, by using Cu(CH₃COO)₂ and AgNO₃ as the precursors. The samples were characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The Cu_xAg hybrid nanostructure showed good particle dispersion, and Cu and Ag metals were well mixed. The catalytic properties of these bimetallic Cu_xAg nanoparticles as model catalysts for the Rochow reaction were explored. Compared to monometallic Cu and Ag nanoparticles, bimetallic Cu_xAg nanoparticles resulted in a much higher silicon conversion, which is attributed to the synergistic electronic effect between Cu and Ag metals. For example, the Cu atom was observed to have a lower electron density in the Cu_xAg bimetallic nanoparticle than that in monometallic Cu nanoparticles, which enhanced the formation of methylchlorosilanes on the silicon surface with chloromethane, demonstrating the significance of the Cu_xAg bimetallic catalysts in catalytic reactions during organosilane synthesis. The insights gained in this study should be conducive to the design of good Cu-based catalysts for the Rochow reaction.