Electronic Structure Engineering of PtZn Alloys to Accelerate Dehydrogenation for Efficient Ammonia Oxidation

Ammonia oxidation reaction (AOR) catalyzed by Pt faces sluggish kinetics due to poisoning by *NHx intermediates and Nad species. While the Oswin-Salomon (O–S) pathway is hindered by high Nad desorption barriers, the Gerischer-Maurer (G–M) mechanism circumvents Nad formation but is limited by high activation energies for *NHx dehydrogenation. In this study, PtZn alloys were synthesized by incorporating low-electronegativity Zn to precisely tune the electronic structure of Pt, resulting in significant enrichment of the d-electron density and a downshift of the d-band center. This electronic modulation weakens the Pt-*NHx bond strength, thereby optimizing the G–M pathway. As a result, the activation energy for the rate-limiting *NH2 dehydrogenation step is notably reduced, promoting faster intermediate turnover and enhancing overall catalytic kinetics. Additionally, operando Raman spectroscopy directly reveals the formation of *N2Hy species on Pt33Zn1, providing compelling evidence that the optimized catalyst follows the G–M mechanism. Impressively, the optimized Pt33Zn1 demonstrates exceptional AOR performance, achieving an onset potential of 0.49 V and a remarkable mass activity of 83.45 A g–1 (peak current density: 25.12 mA cm–2) at 5 mV s–1. These values surpass those of commercial PtIr/C (40%) by 4-fold and 10-fold, respectively. This kinetic enhancement underscores the potential of Pt33Zn1 as a high-performance AOR catalyst.