Regulation of Rate‐Determining Step on (Rh_xNi_1‐x)₂P for Enhanced Alkaline Hydrogen Oxidation Reaction

Abstract

The development of cost‐efficient Pt‐group metals (PGM)‐based electrocatalysts with low noble metal loading for alkaline hydrogen oxidation reaction (HOR) remains challenging for practical applications of anion exchange membrane fuel cells (AEMFCs). Here we successfully synthesized a series of (RhxNi1−x)2P catalysts with satisfying HOR performance in alkaline media. Especially, (Rh0.3Ni0.7)2P−C exhibits an excellent mass activity of 1.274 mA μgPGM−1, 7‐times higher than that of Rh−C. Density functional theory (DFT) calculations and experimental results indicate that benefiting from the synergistic effect of Rh sites with Ni2P, the hydroxyl binding energy (OHBE) is enhanced on the optimized P sites of (RhxNi1−x )2P, which, together with the accelerated water desorption behavior derived from the downshifted d‐band center of Rh sites in (RhxNi1−x )2P, contributes to speeding up the water formation step and thus resulting in the translation of rate‐determining step, as well as the enhanced alkaline HOR performance.