Constructing Ru@C<sub>3</sub>N<sub>4</sub>/Cu Tandem Electrocatalyst with Dual‐Active Sites for Enhanced Nitrate Electroreduction to Ammonia
Yinan Zheng, Mingxin Qin, Xin Yu, Yao Hu, Wenhua Zhang, Gang Xie, Xiaohui Guo
Abstract
Abstract Electroreduction of nitrate to ammonia reaction (NO 3 − RR) is considered as a promising carbon‐free energy technique, which can eliminate nitrate from waste‐water also produce value‐added ammonia. However, it remains a challenge for achieving satisfied ammonia selectivity and Faraday efficiency (FE) due to the complex multiple‐electron reduction process. Herein, a novel Tandem electrocatalyst that Ru dispersed on the porous graphitized C 3 N 4 (g‐C 3 N 4 ) encapsulated with self‐supported Cu nanowires (denoted as Ru@C 3 N 4 /Cu) for NO 3 − RR is presented. As expected, a high ammonia yield of 0.249 mmol h −1 cm −2 at −0.9 V and high FE NH3 of 91.3% at −0.8 V versus RHE can be obtained, while achieving excellent nitrate conversion (96.1%) and ammonia selectivity (91.4%) in neutral solution. In addition, density functional theory (DFT) calculations further demonstrate that the superior NO 3 − RR performance is mainly resulted from the synergistic effect between the Ru and Cu dual‐active sites, which can significantly enhance the adsorption of NO 3 − and facilitate hydrogenation, as well as suppress the hydrogen evolution reaction, thus lead to highly improved NO 3 − RR performances. This novel design strategy would pave a feasible avenue for the development of advanced NO 3 − RR electrocatalysts.