Boronization of Nickel Foam for Sustainable Electrochemical Reduction of Nitrate to Ammonia

by Zhonghua Xue, Han-Cheng Shen, Peirong Chen, Guang-Xue Pan, Wei-Wei Zhang, Wei-Meng Zhang, Shi-Nan Zhang, Xin-Hao Li, Cafer T. Yavuz
ACS Energy Letters Year: 2023 DOI:


Electrochemical reduction of aqueous nitrates has emerged as a sustainable and practical approach in combining water treatment and ammonia fertilizer synthesis. However, the development of highly integrated catalytic electrodes with consistently high activity from non-noble metals remains a challenging issue despite the potential to greatly decrease costs and promote real-world applications. Here, we report a high-performance electrode with electron-abundant surfaces obtained from direct boronization of nickel foam, rendering a stable ammonia yield rate of 19.2 mg h–1 cm–2 with high Faradaic efficiency of 94% for NO3–-to-NH3 conversion. The microprocessing lowers the work function and initiates a local electric field for the nickel foam by converting acid-stable surface nickel oxides into dyadic nanosheets composed of metallic nickel and amorphous nickel borates, thus promoting the adsorption and transformation of nitrate anions. Furthermore, the spent electrode enables a rapid and effective regeneration by undergoing another round of boronization, which ensures a long lifetime for the practical application of our electrode design