Efficient Ammonia Synthesis from Nitrate Catalyzed by Au/Cu with Enhanced Adsorption Ability
Bo Bi, Anqi Dong, Miaomiao Shi, X. F. Sun, Hongrui Li, Kang Xia, Rui Gao, Zhe Meng, Zeyu Chen, Tongwen Xu, Jun‐Min Yan, Qing Jiang
Abstract
The traditional method for synthesizing NH 3 is the Haber–Bosch process which results in high‐fuel consumption and environmental pollution. Therefore, ecofriendly electrochemical synthesis of NH 3 through nitrate (NO 3 − ) reduction is a good choice. Herein, an integral Au/Cu electrode to catalyze NO 3 − reduction to NH 3 is introduced. The catalyst exhibits not only the highest NH 3 yield rate (73.4 mg h −1 cm −2 ) up to now but also a very high Faradaic efficiency of 98.02% at −0.7 V at room temperature. It is commonly believed that the transformation of NO 3 − to nitrite (NO 2 − ) is an obstacle to the NH 3 generation from NO 3 − reduction. Surprisingly, unlike most of the other catalysts, Au/Cu exhibits better activity for NO 3 − reduction than that for NO 2 − reduction. Based on the detailed experimental and density functional theory calculations, the excellent performance of Au/Cu for selective NO 3 − reduction lies in the enhanced adsorption capabilities of Au/Cu to NO 3 − in the alkaline environment and the lower energy barriers of the electrochemical reduction reaction.