Selective and Long‐Term Stable Ammonia Electrolysis Using Pt–WO _x Catalysts with Suppressed NO _x Formation and Enhanced Activity

Ammonia electrolysis presents a promising strategy for low-voltage hydrogen production; however, its advancement is impeded by limitations in electrocatalyst performance due to sluggish reaction kinetics and deactivation caused by strongly adsorbed nitrogen-containing intermediates. In this study, a photodeposited Pt on tungsten suboxide (WO_x) nanowires (Pt-WO_x (P)) is introduced as a bifunctional electrocatalyst for ammonia electrolysis. The photodeposition induces strong metal-support interaction, resulting in robust interfacial bonding between Pt and WO_x and facilitating electron transfer from WO_x to Pt. ATR-SEIRAS (attenuated total reflection-surface enhanced infrared absorption spectroscopy) identifies the Gerischer-Mauerer (G-M) mechanism through absorbance peaks corresponding to NH₂ and N_xH_y (x = 1-2) and reveals effective suppression of NO_x poisoning on Pt-WO_x (P). DFT confirms the electronic modulation of Pt significantly lowers the energy barrier of the rate-determining step (RDS) for the conversion of *NH₂ to *NH by enhancing hydrogen bonding of *NH and *OH. As a result, Pt-WO_x (P) exhibits outstanding AOR activity, achieving a high peak current density of 49.69 mA cm^-2. Furthermore, it demonstrates remarkable stability for over 120 h during ammonia electrolysis. In an MEA-based flow cell, Pt-WO_x (P) delivers current densities exceeding 500 mA cm^-2, underscoring its potential as a bifunctional catalyst for ammonia electrolysis applications.