Efficient Ammonia Synthesis from Nitrate Catalyzed by Au/Cu with Enhanced Adsorption Ability

• Published in: Small Structures
• Main Authors: Bo Bi, An-Qi Dong, Miao-Miao Shi, Xue-Feng Sun, Hong-Rui Li, Xia Kang, Rui Gao, Zhe Meng, Ze-Yu Chen, Tong-Wen Xu, Jun-Min Yan, Qing Jiang
• Format: Article
• Language: English
• Published: Wiley-VCH 2023-04-01
• Subjects: adsorption ability; ammonia synthesis; Au/Cu; catalysts; nitrate/nitrite reduction reactions
• Online Access: https://doi.org/10.1002/sstr.202200308

The traditional method for synthesizing NH3 is the Haber–Bosch process which results in high‐fuel consumption and environmental pollution. Therefore, ecofriendly electrochemical synthesis of NH3 through nitrate (NO3−) reduction is a good choice. Herein, an integral Au/Cu electrode to catalyze NO3− reduction to NH3 is introduced. The catalyst exhibits not only the highest NH3 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 NO3− to nitrite (NO2−) is an obstacle to the NH3 generation from NO3− reduction. Surprisingly, unlike most of the other catalysts, Au/Cu exhibits better activity for NO3− reduction than that for NO2− reduction. Based on the detailed experimental and density functional theory calculations, the excellent performance of Au/Cu for selective NO3− reduction lies in the enhanced adsorption capabilities of Au/Cu to NO3− in the alkaline environment and the lower energy barriers of the electrochemical reduction reaction.