Effect of halogen-modification on Ag catalyst for CO2 electrochemical reduction to syngas from NH4HCO3 electrolyte. Issue 6 (December 2021)

• Record Type: Journal Article
• Authors: Li, Huiyi; Gao, Jianmin; Shan, Jingjing; Du, Qian; Zhang, Yu; Guo, Xin; Xie, Min; Wu, Shaohua; Wang, Zhijiang
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 6(2021)
• Publication Date: 2021-12
• Subjects: CO2 electroreduction -- Ammonium bicarbonate electrolyte -- Ag catalyst -- Halogen modification -- Syngas; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.106415
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: The crucial technology of combining the excess capacity from power plants and the electrocatalytic reduction method to realize the direct conversion of products from ammonia-based CO2 capture to syngas of CO and H2 is to research and develop catalysts for direct electrochemical NH4 HCO3 reduction. The electrochemical performance of halogen (Cl, Br, and I)-modified Ag electrodes by cyclic voltammetry (CV) oxidation and reduction treatment carried out in supersaturated NH4 HCO3 electrolyte without CO2 bubbling. All of the halogen-modified catalysts realized the direct reduction of NH4 HCO3 to syngas of CO and H2 . Among them, the Br-modified Ag catalysts have CO Faradaic efficiency of 74.0% at − 0.5 V versus reversible hydrogen electrode much higher than that of Cl- (38%) and I- (39.8%) modified Ag catalysts. The H2 /CO ratio on the Br-modified Ag catalyst is approximately 0–3, which is conducive to the reserve of multi-carbon raw materials and the process of Fischer Tropsch synthesis. Furthermore, the Cl-modified Ag catalyst could control the H2 /CO ratio of syngas in a wide range of 0.6–6.0 under low potential (from −0.3 to −0.7 V), which is beneficial to apply to different industrial production. Graphical Abstract: ga1 Highlights: Halogen-modified Ag catalysts could directly electro-reduce NH4 HCO3 to syngas without CO2 bubbling. Br-modified Ag catalysts have higher CO Faraday efficiency than Cl- and I-modified Ag catalysts. Cl-modified Ag catalysts show a wide range of H2 /CO ratios at low overpotential.