AuPd nanoporous dendrites: High electrocatalytic activity and surface plasmon-enhanced stability for ethanol electrooxidation

Abstract

The design of electrocatalysts with high activity and enhanced durability for ethanol oxidation reaction (EOR) is critical for the commercialization of direct ethanol fuel cells (DEFCs). Herein, a AuPd nanoporous dendritic (AuPd NPD) catalyst was reported, which exhibited high electrocatalytic activity and stability for EOR by dealloying the ternary alloy AuxPdyNi95 with a low atom content of noble metals (5 at.%). The morphologies of AuPd nanopores varied from islands to dendrites by adjusting the Ni content from 80 at.% to 95 at.%. The activity of AuPd NPD was improved up to 8.2 A mg–1Pd by tuning the Au/Pd atomic ratio, which was 16.4 times higher than commercial Pd/C (0.5 A mg–1Pd). The current of all AuPd NPD catalysts remained above 85 % of their initial values after 500 CV cycles, indicating the good electrocatalytic cycle durability of NPD structures. Density functional theory (DFT) calculations revealed that the improved activity stemmed from the upshift of Pd d-band center. The CA long-term stability of Au3.5Pd1.5 NPD was further improved to 2.05 A mg–1Pd even after 6000 s of operation under simulated solar irradiation, which was 3.6 times higher than that without simulated solar irradiation (0.57 A mg–1Pd). The enhanced stability was attributed to the surface plasmon resonance effect of Au nanostructures excited by visible light excitation.