Growth of FeO Nanorod Arrays on Carbon Cloth with Rapid Charge Transfer for Efficient Nitrate Electroreduction to Ammonia.

Electrochemical reduction of nitrate to ammonia (NH), a green NH production route upon combining with renewable energy sources, is an appealing and alternative method to the Haber-Bosch process. However, this process not only involves the complicated eight-electron reduction to transform nitrate into various nitrogen products but simultaneously suffers from the competitive hydrogen evolution reaction, challenged by a lack of efficient catalysts. Herein, the growth of FeO nanorod arrays on carbon cloth (FeO NRs/CC) is reported to exhibit a high NH yield rate of 328.17 μmol h cm at -0.9 V versus RHE, outperforming most of the reported Fe catalysts. An growth strategy provides massive exposed active sites and a fast electron-transport channel between the carbon cloth and FeO, which accelerates the charge-transport rate and facilitates the conversion of nitrate to NH. Raman spectroscopy in conjunction with attenuated total reflection Fourier transform infrared spectroscopy reveals the catalytic mechanism of nitrate to NH. Our study provides not only an efficient catalyst for NH production but also useful guidelines for the pathways and mechanism of nitrate electroreduction to NH.