In situ generating Cu2O/Cu heterointerfaces on the Cu2O cube surface to enhance interface charge transfer for the Rochow reaction

Abstract

In heterogeneous catalysis, successful design and construction of the desired oxide–metal interface are critical to catalytic function due to the significant interfacial effects. However, there are still challenges and obscurities in constructing and understanding the structure of various interfacial sites and their oxide–metal interactions. In the present work, a series of cubic Cu/Cu₂O hetero-nanoparticles were synthesized by in situ surface restructuring cubic Cu₂O nanoparticles via a simple reduction treatment. These nanoparticles were further used as the model catalyst for the Rochow reaction, an important industrial process for synthesizing organosilicon polymers. It is found that cubic Cu/Cu₂O with appropriate heterointerfaces exhibited improved dimethyldichlorosilane (M2) selectivity, Si conversion, and stability because of a strong interaction between the Cu/Cu₂O interface. The latter originates from the formation of Schottky junctions that enhance the charge transfer efficiency and the subsequent reduction of Cu⁺ into Cu* (the active Cu atoms). Moreover, the easier cleavage of the Si–Si bond along the {110} crystal plane effectively generates Si* (the free Si atoms), which leads to inclined grooves on the surface of Si particles. The established transport and diffusion channels of Cu* and Si* greatly promoted the formation of the Cu₃Si active phase and the subsequent methyl chlorosilane. This work provides a new fundamental understanding of Cu-based catalysts for the Rochow reaction and reveals a clear relationship between the Cu₂O/metal heterointerface and the catalytic performance.