Reversible Hydrogen Acceptor–Donor Enables Relay Mechanism for Nitrate‐to‐Ammonia Electrocatalysis
Yuefei Li, Ye Liu, Mingkai Zhang, Linsen Li, Zhao Jiang, Bingying Han, Baojun Wang, Jiayuan Li, Jiayuan Li
Abstract
Abstract Electrocatalytic nitrate reduction is a crucial process for sustainable ammonia production. However, to maximize ammonia yield efficiency, this technology inevitably operates at the potentials more negative than 0 V vs. RHE, leading to high energy consumption and competitive hydrogen evolution. To eradicate this issue, hydrogen tungsten bronze (H x WO 3 ) as reversible hydrogen donor‐acceptor is partnered with copper (Cu) to enable a relay mechanism at potentials positive than 0 V vs. RHE, which involves rapid intercalation of H into H x WO 3 lattice, prompt de‐intercalation of the lattice H and transfer onto Cu, and spontaneous H‐mediated nitrate‐to‐ammonia conversion on Cu. The resulting catalysts demonstrated a high ammonia yield rate of 3332.9±34.1 mmol g cat −1 h −1 and a Faraday efficiency of ~100 % at 0.10 V vs. RHE, displaying a record‐low estimated energy consumption of 17.6 kWh kg ammonia −1 . Using these catalysts, we achieve continuous ammonia production in an enlarged flow cell at a real energy consumption of 17.0 kWh kg ammonia −1 .