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

Abstract 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 NH 2 and N x H 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 *NH 2 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.