Electrocatalytic reduction of nitrate to ammonia on low-cost manganese-incorporated Co3O4 nanotubes

• Published in: Applied catalysis. B, Environmental Environmental, 2023-05, Vol.324, p.122293, Article 122293
• Main Authors: Liu, Di, Qiao, Lulu, Chen, Yuyun, Zhou, Pengfei, Feng, Jinxian, Leong, Chon Chio, Ng, Kar Wei, Peng, Shengjie, Wang, Shuangpeng, Ip, Weng Fai, Pan, Hui
• Format: Article
• Language: English
• Subjects: Ammonia yield; DFT calculations; Electrocatalytic nitrate reduction reaction; Mn incorporation; Spinel Co3O4
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2022.122293

Spinel oxides, especially Co3O4, have been considered as ideal electrocatalysts for electrocatalytic nitrate reduction reaction (e-NO3RR). However, their application in e-NO3RR is still limited because of relatively low activity and selectivity under high potential. Herein, we present that the incorporation of manganese (Mn) into the Co3O4 lattice can achieve the high activity and selectivity in e-NO3RR. The Mn-incorporated Co3O4 nanotubes show a remarkable e-NO3RR activity with a high ammonia yield rate of 35 mg h−1 cm−2 and excellent selectivity with a Faraday efficiency for ammonia up to 99.5% in neutral media, which are much better than those of transition-metal oxides. Our calculations further show that the replacement of Co by Mn can tune the adsorption behavior of intermediates, and thus reduces the limiting potential of e-NO3RR. We believe that the findings provide an insightful guidance to engineer the spinel oxides for enhanced performance towards ideal products. [Display omitted] •Mn-incorporated Co3O4 nanotubes show the highest ammonia yield rate among transition-metal based oxides.•Mn-incorporated Co3O4 nanotubes show high selectivity and stability of e-NO3RR.•the Mn ion only partially replaces Co in the CoO6 octahedrons of spinel Co3O4.•The synergistically catalytic mechanism for Mn-incorporated Co3O4 was surveyed.