Halide-guided active site exposure in bismuth electrocatalysts for selective CO2 conversion into formic acid

Abstract It remains a challenge to identify the active sites of bismuth catalysts in the electrochemical CO 2 reduction reaction. Here we show through in situ characterization that the activation of bismuth oxyhalide electrocatalysts to metallic bismuth is guided by the halides. In situ X-ray diffraction results show that bromide promotes the selective exposure of planar bismuth surfaces, whereas chloride and iodide result in more disordered active sites. Furthermore, we find that bromide-activated bismuth catalysts outperform the chloride and iodide counterparts, achieving high current density (>100 mA cm –2 ) and formic acid selectivity (>90%), suggesting that planar bismuth surfaces are more active…

• ES
  European Synchrotron Radiation Facility
• UU
  Universiteit Utrecht
• TU
  Technische Universiteit Eindhoven
• NO
  Nederlandse Organisatie voor Wetenschappelijk Onderzoek
• UA
  Universiteit Antwerpen