Bimetallic Atomic Catalysts for Efficient Hydrogen Oxidation Reactions in Alkaline Media

The sluggish kinetics of the hydrogen oxidation reaction (HOR) in alkaline media lead to significantly high Pt loadings in alkaline fuel cell (AFC) systems. Dual-atom catalysts (DACs) with dual-atomic active sites have emerged as promising alternatives. Herein, we investigated 28 heterometallic (M1M2/CN6, M1 = Ru/Ir, M2 = 3d Ti–Cu, 4d Zr–Ag) supported on N-doped graphene via density functional theory calculations (DFT). Our results reveal that the N-coordinated network in M1M2/CN6 reconstructs the electronic environment of bimetallic sites, forming synergistic dual-functional active centers where the M1 d-band center governs H* adsorption, whereas the M2 d-band center modulates OH* binding. The H* adsorption free energy (ΔGH*) exhibits a negative linear correlation with the M1 d-band center, whereas the OH* adsorption free energy (ΔGOH*) linearly weakens as the M2 d-band center shifts downward, establishing a dual-variable adsorption regulation mechanism. A composite descriptor |ΔGH*|+0.8ΔGOH* reveals a volcano relationship with HOR barriers, with optimal activity at ΔGH* = 0 eV and ΔGOH* = −0.22 eV. Notably, the Ru–Fe and Ir–Mn DACs achieve near-ideal adsorption balances, yielding ultralow HOR free energy barriers (0.35 and 0.25 eV). This work establishes Ru–Fe/Ir–Mn DACs as efficient AFC anode catalysts, providing insights into rational HOR bimetallic catalyst design.