The effects of Co/Ce loading ratio and reaction conditions on CDRM performance of CoCe/ZrO2 catalysts

This work mainly aims to establish a link between Co/Ce loading ratio in CoCe/ZrO2 catalysts and their Carbon Dioxide Reforming of Methane (CDRM) performance. In this context, catalysts with different Co and Ce loadings were prepared and characterized via BET, XRD, HRTEM-EDX, XPS and Raman, and parametrically tested under different CDRM conditions. Dispersion of Co particles was nonhomogeneous on all samples. For the sample with the highest Co/Ce ratio (10%Co2%Ce/ZrO2), higher amount of lattice oxygen vacancies and lowest degree of ceria reduction were determined. Raman analysis showed that graphitic carbon coexisted with amorphous carbon on the surface of all spent samples. The extent of side reactions prevailed in determining selectivity. It was expressed that both CoCe synergistic interaction and synchronous contribution of Ce and ZrO2 were enhanced for the samples having lower Co/Ce ratio. It was confirmed that Ce is only responsible for oxygen transfer but not its formation.