Coordinatively unsaturated nickel–nitrogen sites towards selective and high-rate CO2 electroreduction. Issue 5 (3rd April 2018)

• Record Type: Journal Article
• Authors: Yan, Chengcheng; Li, Haobo; Ye, Yifan; Wu, Haihua; Cai, Fan; Si, Rui; Xiao, Jianping; Miao, Shu; Xie, Songhai; Yang, Fan; Li, Yanshuo; Wang, Guoxiong; Bao, Xinhe
• Is Part Of: Energy & environmental science. Volume 11:Issue 5(2018)
• Page Start: 1204
• Page End: 1210
• Publication Date: 2018-04-03
• Subjects: Energy conversion -- Periodicals; Fuel switching -- Periodicals; Environmental sciences -- Periodicals; Environmental chemistry -- Periodicals; 333.79
• DOI: 10.1039/c8ee00133b
• Languages: English
• ISSNs: 1754-5692

Abstract

Abstract : Coordinatively unsaturated Ni–N active sites facilitate CO2 electroreduction and inhibit the competitive hydrogen evolution reaction, demonstrating selective and high-rate CO2 electroreduction. Abstract : High Faradaic efficiency and appreciable current density are essential for future applications of the electrochemical CO2 reduction reaction (CO2 RR). However, these goals are difficult to achieve simultaneously due to the severe side reaction – the hydrogen evolution reaction (HER). Herein, we successfully synthesized coordinatively unsaturated nickel–nitrogen (Ni–N) sites doped within porous carbon with a nickel loading as high as 5.44 wt% by pyrolysis of Zn/Ni bimetallic zeolitic imidazolate framework-8. Over the Ni–N composite catalysts, the CO current density increases with the overpotential and reaches 71.5 ± 2.9 mA cm −2 at −1.03 V ( vs. a reversible hydrogen electrode, RHE), while maintaining a high CO Faradaic efficiency of 92.0–98.0% over a wide potential range of −0.53 to −1.03 V ( vs. the RHE). Density functional theory calculations suggest that the CO2 RR occurs more easily than the HER over the coordinatively unsaturated Ni–N site. Therefore, highly doped and coordinatively unsaturated Ni–N sites achieve high current density and Faradaic efficiency of the CO2 RR simultaneously, breaking current limits in metal–nitrogen composite catalysts.