CuCl-CatalyzedHydrogenation of Silicon Tetrachloridein the Presence of Silicon: Mechanism and Kinetic Modeling.

TheCuCl-catalyzed hydrogenation of silicon tetrachloride (STC)in the presence of silicon was conducted in a fixed-bed reactor. Thesolid mass from different reaction stages was collected and characterizedusing X-ray diffraction (XRD) and scanning electron microscopy coupledwith energy-dispersive X-ray spectroscopy (SEM-EDX). The characterizationresults were used to develop a novel reaction mechanism. This mechanismis remarkable in that the Cu–Si surface species acted as botha catalyst and a solid reactant and could be regenerated via Cu diffusioninto the bulk silicon phase. Different kinetic models were formulatedby employing the Langmuir–Hinshelwood (L–H) and Eley–Rideal(E–R) approaches. Model discrimination was used to select akinetic model based on the E–R mechanism, in which the surfacereaction between the adsorbed STC and gas-phase H2overthe Cu3Si active sites was assumed to be the rate-determiningstep (RDS). The kinetic parameters were estimated using nonlinearregression, and the model predictions were in good agreement withthe experimental data. [ABSTRACT FROM AUTHOR]