Deciphering the Promoting Effect of Zn on CuO for\nDimethyldichlorosilane Production\nvia the Rochow-Muller Reaction

Zinc\n(Zn) is commonly used as a promoter in Cu-based catalysts\nto boost the production of organosilane monomers during the Rochow-Müller\nreaction. However, the effect of Zn on the phase change of Cu-based\ncatalysts in the reaction process is not yet fully understood. In\nthis study, we prepared two Zn-modified CuO catalysts using simple\nball milling (Zn–CuO) and physical mixing (Zn+CuO) methods.\nWe found that adding Zn into CuO enhanced the adsorption of methyl\nchloride on the CuO surface, thereby promoting the sequential phase\ntransformation of CuO to Cu<sub>2</sub>O and then to Cu and further\nto CuCl. Moreover, CuCl, as a key intermediate phase, could diffuse\ninto Si powder and form Cu<sub>3</sub>Si under high-temperature conditions.\nCompared to CuO and Zn+CuO, Zn–CuO underwent a faster phase\ntransformation, facilitating the generation of the active Cu<sub>3</sub>Si phase and enhancing the dimethyldichlorosilane selectivity and\nSi conversion. This study has clarified the role of the Zn promoter\nin the phase transformation of CuO catalysts in the Rochow-Müller\nreaction. Understanding this mechanism is crucial to designing more\nefficient catalysts.