High-Efficiency Electrosynthesis of Ammonia with Selective Reduction of Nitrate in Neutral Media Enabled by Self-Supported Mn<sub>2</sub>CoO<sub>4</sub> Nanoarray
Lisi Xie, Qian Liu, Shengjun Sun, Long Hu, Longcheng Zhang, Donglin Zhao, Qin Liu, Jie Chen, Jun Li, Ling Ouyang, Abdulmohsen Ali Alshehri, Mohamed S. Hamdy, Qingquan Kong, Xuping Sun
Abstract
Ambient ammonia synthesis by electroreduction of nitrate (NO3–) provides us a sustainable and environmentally friendly alternative to the traditional Haber–Bosch process. In this work, Mn2CoO4 nanoarray grown on carbon cloth (Mn2CoO4/CC) serves as a superior electrocatalyst for efficient NH3 synthesis by selective reduction of NO3–. When operated in 0.1 M PBS with 0.1 M NaNO3, Mn2CoO4/CC reaches a high Faraday efficiency of 98.6% and a large NH3 yield up to 11.19 mg/h/cm2. Moreover, it exhibits excellent electrocatalytic stability. Theory calculations show that the Mn2CoO4 surface has strong interaction with NO3–, which can effectively inhibit the occurrence of hydrogen evolution, beneficial for NO3–-to-NH3 conversion.