Effective ethanol-to-CO2 electrocatalysis at iridium-bismuth oxide featuring the impressive negative shifting of the working potential

Abstract

Since low overpotential for the anodic ethanol oxidation reaction (EOR) can favor the higher output voltage and power of direct ethanol fuel cells (DEFCs), it is critical to design new EOR catalysts with efficient ethanol-to-CO2 activity at low applied potentials. Thereby, carbon-supported Ir-Bi2O3 (Ir-Bi2O3/C) catalysts with highly dispersive bismuth oxide on the iridium surface are designed and prepared, which can merit splitting the ethanol C–C bond and promoting the oxidation of C1 intermediates at the bifunctional interfaces. The as-obtained Ir-Bi2O3/C catalysts show superior EOR mass activity of up to ca. 2250 mA mg−1Ir. Moreover, they exhibit the record lowest onset oxidation potentials (0.17–0.22 V vs. RHE) and the peak potential (ca. 0.58 V vs. RHE), being 130–300 mV lower than the previous landmark noble metallic catalysts. Furthermore, an apparent C1 pathway faraday efficiency (FEC1) of 28% ± 5.9% at 0.5 V vs. RHE can be obtained at Ir-Bi2O3/C. This work might provide new insights into the new anodic EOR catalysts for increasing the power of DEFCs.