Palladium-Modified Tungsten Carbide for Ethanol Electrooxidation: From Surface Science Studies to Electrochemical Evaluation

Abstract

In this study we report a combined surface science and electrochemical investigation of using palladium-modified tungsten carbide (Pd/WC) as an efficient catalyst for the ethanol oxidation reaction (EOR). Compared to the Pd(111) surface, DFT calculations suggested that the Pd/WC(0001) surface should be less poisoned by the ethanol decomposition intermediates, consistent with surface science results that desorption temperatures of the detected intermediates were lower on the Pd/WC surface. Electrochemical evaluation coupled with in-situ infrared reflection absorption spectroscopy (IRRAS) measurements of 5 wt% Pd/WC/C powder catalysts were then conducted. The EOR activity of the 5 wt% Pd/WC/C catalyst was noticeably enhanced, compared to the benchmark 40 wt% Pd/C. The IRRAS results showed that the EOR products were detected at a lower onset potential on 5 wt% Pd-WC/C than on 40 wt% Pd/C.