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

To address the issue of excessive atmospheric CO 2 levels, electrochemical CO 2 reduction reaction (eCO 2 RR) 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 eCO 2 RR 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/cm 2 with a FE HCOO− of 96.1%. Characterization tests demonstrate that Bi3Sn1Ox's unique porous structure confer superior CO 2 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 CO 2 , favors the generation of the *OCHO intermediate and promotes HCOO − formation. • A nanosheet-stacked microspherical BiSn bimetallic oxide was derived from BiSn-MOF. • High FE HCOO⁻ (>90%) over wide potential range (−0.9 to −1.4 V vs. RHE) was obtained in an H-cell. • A high activity ( j HCOO− of 769 mA/cm 2 ) was achieved in the flow cell. • Bi3Sn1Ox's porous structure increases active sites, enhancing CO 2 adsorption. • Electron transfer between Bi and Sn promotes the formation of the *OCHO intermediate.