Platinum-Decorated Amorphous Sulfurized Palladium Nanowires for Effective Ethanol Oxidation Reaction

Abstract

The mainstream electrocatalysts for direct ethanol fuel cells (DEFCs) are Pt-or Pd-based nanomaterials, which are severely hampered by CO intermediate poisoning and the relatively low selectivity of the C1 pathway in anodic ethanol oxidation reaction (EOR), thereby impeding the efficiency enhancement and practical application of DEFCs. Herein, we report a Pt-decorated amorphous PdS nanowire [denoted as a-Pd(S)NWs/Pt] catalyst with abundant crystalline/amorphous heterogeneous interfacial active sites for alkaline EOR. The a-Pd(S)NWs/Pt was demonstrated a superior EOR mass activity of 6.16 A•mg Pd+Pt −1 , which is 22.81 times over that of commercial Pt/C (0.27 A•mg Pt −1 ) and 34.22 times over that of commercial Pd/C (0.18 A•mg Pd −1). Additionally, the a-Pd(S)NWs/Pt exhibited considerable stability, significantly enhanced resistance to CO poisoning and enhanced selectivity for the EOR C1 pathway. Density functional theory calculations and experimental results further revealed that the optimized CO ads and OH ads binding energies due to the decoration of Pt nanoclusters can be responsible for the enhanced CO resistance and C1 selectivity of a-Pd(S)NWs/Pt. Furthermore, benefiting from its optimized electronic configuration at the interfacial active sites and the appropriate intermediate adsorption capacity, the a-Pd(S)NWs/Pt electrocatalyst was successfully extended to the electrocatalytic methanol and ethylene glycol oxidation reaction systems.