Boosting Hydrogen Oxidation Kinetics by Promoting Interfacial Water Adsorption on d-p Hybridized Ru Catalysts

Abstract

The search for highly efficient and cost-effective electrocatalysts for hydrogen oxidation reaction (HOR) under alkaline electrolytes is essential for the commercial application of anion exchange membrane fuel cells. However, the kinetics of HOR in an alkaline media is much slower than that in an acidic electrolyte, which usually results in orders of magnitude decrease in the catalytic performance. Herein, we report the synthesis of d-p orbital hybridized Ru catalysts through Sn/Ga doping. Density functional theory (DFT) calculations and experimental results including H2-temperature programmed desorption (H2-TPD) and in situ Raman spectra unveil that the electronic structure modification of Ru derived from the unconventional d-p hybridization could lead to the promoted interfacial water adsorption ability and optimized hydrogen adsorption free energy during the alkaline HOR process. As expected, the d-p hybridized Ru catalyst shows much decreased formation energy of water, which contributes to the changed potential-determining step (PDS) and remarkable HOR activity with the mass activity up to 1790 mA mgRu–1. This work not only illustrates the key role of interfacial water adsorption ability but also provides a strategy for rationally designing advanced electrocatalysts for alkaline HOR.