Heterojunction Catalysts for Enhanced Electrochemical Nitrate Reduction to Ammonia: Mechanisms, Advances, and Prospects
Fenghong Sun, Wenlin Zhang, Fengshou Yu, Lu‐Hua Zhang
Abstract
Abstract The electrochemical catalytic nitrate reduction reaction (NO 3 RR) has been emerging as a significant supplement for industrial NH 3 synthesis. While the catalysts are still facing the challenges of low yield, strong hydrogen evolution reaction (HER), and are unable to adapt to the change of nitrate concentration in industrial wastewater. A heterojunction is a junction structure formed through atomic‐level interfacial coupling between two or more semiconductor materials (or between a semiconductor and a metal/insulator) with different crystal structures or band structures. The mechanism of heterojunction catalysis involves interfacial charge transport, which regulates the electronic structure and catalytic properties of the materials. This charge transfer can lead to the formation of electron‐deficient or electron‐rich centers, serving as active sites for the adsorption and activation of reaction intermediates. The review discusses various types of heterojunction catalysts. The heterojunction electrocatalysts exhibit significant potential in enhancing NO 3 RR activity and selectivity through synergistic effects, built‐in electric fields, and other strategies, which can improve the electron transfer rate, regulate the conductivity, and optimize the active site density. Despite challenges in material preparation and mechanism elucidation, the increasing interest and research progress in this field indicate a promising future for the industrial application of heterojunction catalysts in NO 3 RR.