Metal-organic framework-derived BiSn bimetallic oxides for the electrocatalytic reduction of CO₂ to formate

AbstractTo address the issue of excessive atmospheric CO₂ levels, electrochemical CO₂ reduction reaction (eCO₂RR) to fuels and chemicals has been extensively studied. Herein, we report a metal-organic framework-derived spherical catalyst Bi3Sn1Ox, consisting of stacked nanosheets, by combining hydrothermal and pyrolysis methods. Bi3Sn1Ox demonstrates outstanding performance in eCO₂RR for HCOO− production, achieving over 94% FE_HCOO− in H-cells across a potential range of −0.9 V to −1.4 V. It also exhibits considerable current density in flow cells, reaching up to 800 mA/cm2 with a FE_HCOO− of 96.1%. Characterization tests demonstrate that Bi3Sn1Ox's unique porous structure confer superior CO₂ adsorption capacity. Furthermore, the electron transfer between Bi and Sn in Bi3Sn1Ox creates a positive charge center at Sn sites, which inhibits nucleophilic reactions on CO₂, favors the generation of the *OCHO intermediate and promotes HCOO− formation.