Cu3Si formed by vacuum evaporation deposition enhances hydrogenation of silicon tetrachloride

The efficient conversion of SiCl4 to SiHCl3 still presents considerable challenges for the Siemens process. The enhancement of solid-solid interaction between catalyst and silicon particles in hydrogenation of SiCl4 is viewed as a top priority. In this study, CuCl catalyst and silicon particles mixture heated at the vacuumized tube bomb reactor is found to be an effective pretreatment strategy for obtaining excellent catalytic performance as much as 21.2% under the optimum conditions. The vacuum evaporation deposition is favorable for the deposition uniformly of gaseous CuCl on the surfaces of silicon particles and the formation of Cu3Si. The moderate temperature and time of the vacuum evaporation deposition pretreatment will promote the growth of copper compounds and shorten the induction period of SiCl4 hydrogenation reaction. When CuCl and free copper of the pretreated sample are dissolved by NH4OH, the SiCl4 conversion still maintains 19.8%. Cu3Si is employed as the active phase expresses good catalytic performance where the conversion of SiCl4 is positively correlated with the content of Cu3Si.