Enabling Direct Experimental Matched Activity Evaluation and Identification of a Dominant Modulation Factor via Theoretical Alkaline HOR Kinetic Analysis at the Catalyst/Electrolyte Interface

Optimizing the activity of alkaline hydrogen oxidation reaction (HOR) catalysts is pivotal for advancing the performance of alkaline fuel cells. However, the controversial modulation strategies for catalytic activity, along with the chasm between theoretical and experimental investigations, necessitate extensive trial-and-error experiments to maximize the alkaline HOR activity. Here, a comprehensive framework centered on theoretical kinetic analysis is introduced, integrating theoretical and experimental evaluation of alkaline HOR activity on Pt3M (M = Cr, Co, Pd, Sn, and Ir) catalysts, to address this challenge. This strategy not only validates electronic property and oxophilicity modulation factors of catalytic activity (with an upshift of the band center (εd) and increased oxophilicity compared to Pt), but also achieves an overlap ratio (Roverlap) of 92.94% to 99.39% between simulated and experimental polarization curves. Compared with oxophilicity modulation, the electronic property emerges as the dominant modulation factor governing alkaline HOR activity, as evidenced by their strong correlations with the free energy (Ea) of the rate-determining step and the exchange current density (i0), with degrees of correlation values of −0.98 and 0.98, respectively. This work bridges the chasm between theoretical and experimental investigation and advances the rational design and efficient synthesis of energy conversion catalysts.