Comparison of O-H, C-H, and C-O Bond Scission Sequence of Methanol on Tungsten Carbide Surfaces Modified by Ni, Rh, and Au

Controlling the decomposition pathways of methanol is of significant importance to applications such as methanol reforming and direct methanol fuel cells. An understanding of the reaction of methanol on tungsten carbide (WC) and metal-modified WC surfaces should provide useful input for the utilization of these materials as alternative catalysts for reforming and fuel cell applications. In this study, we have performed a combined theoretical and experimental investigation to determine how the O-H, C-H, and C-O bond scission pathways are affected by modifying WC surfaces with Ni, Rh, or Au. Density functional theory results show that the methoxy species bonds strongly on Rh/WC and Ni/WC and should lead to higher activity toward methanol decomposition. In comparison, the binding energy on Au/WC is considerably lower. Temperature-programmed desorption and high-resolution electron energy loss spectroscopy show that Rh/WC has the highest activity, followed by Ni/WC and Au/WC. The current results are also compared with previous studies of methanol decomposition on Pt/WC to determine the general trend in the modification effect by different metals.