Creating Moderate Local Reaction Environment on Nanoporous Cu <sub>2</sub> O for Electrocatalytic Ammonia Oxidation to Nitrite and Nitrate
Lin Yang, Yanqin Liang, Hui Jiang, Zhaoyang Li, Shuilin Wu, Zhonghui Gao, Zhenduo Cui, Shengli Zhu, Wence Xu
Abstract
Abstract Electrochemical ammonia oxidation reaction (AOR) presents a promising strategy for sustainable nitrite and nitrate (NO x − ) production. Conventional noble metal‐based AOR catalysts often yield undesired dinitrogen and suffer from AOR intermediates poisoning. Herein, nanoporous Cu 2 O (np–Cu 2 O) prepared by dealloying plus annealing is reported as an efficient AOR electrocatalyst for NO x − production. The np–Cu 2 O undergoes structural reconstruction during AOR to form the Cu 2 O/CuO heterostructure with moderate Lewis acidity, which optimizes the *NH 2 adsorption and improves the interface water structure to regulate the local OH − distribution, significantly reducing the energy barrier for AOR. Consequently, the np–Cu 2 O exhibits a total NO x − yield rate of 134.62 µmol cm −2 h −1 with a high total Faradaic efficiency of 90.8%. Additionally, efficient and stable NO x − synthesis is achieved in an electrolyzer coupled with AOR and oxygen reduction reaction (ORR), which delivers an onset potential of ≈0.5 V and a high NO x − Faradaic efficiency of 94.6% at 10 mA cm −2 . This work would shed light on the design of high‐efficiency electrocatalysts via Lewis acidity regulation for the efficient NO x − production by AOR.