Ceria-Mediated Dynamic Sn0/Sn?+ Redox Cycle for CO2 Electroreduction

Electrocatalytic CO2 reduction has been considered an effective carbon neutrality as well as energy storage strategy integrated with renewable electricity. CO2 conversion to formate is a feasible route using earth-abundant and nontoxic tin-based catalysts. However, they suffer from degradation and thus decrease in formate selectivity during operation. Guided by density functional theory (DFT) calculations, herein, we synthesized CeO2-SnO2 heterostructures by a facile electrospinning method, which exhibited a maximum formate partial current density of similar to 500 mA center dot cm-2 with 87.1% faradaic efficiency and a long-term stability in a flow cell. Proved by in situ attenuated total reflectance infrared absorption spectroscopy (ATR-IRAS) and Raman spectra as well as post-X-ray photoelectron spectroscopy (XPS) analysis, a dynamic CeO2-mediated Sn0/Sn delta+ redox cycle mechanism was proposed: oxygen vacancies generated on cerium oxides prompted water dissociation to produce *OH and *H species, where the former oxidize Sn0 into active Sn delta+, facilitating the conversion of CO2 to the key intermediate *OCHO with the help of the latter. This work may provide a general strategy to design stable and efficient catalysts for practical CO2 electrolyzers.

Automated summary

Guided by density functional theory (DFT) calculations, CeO2-SnO2 heterostructures with high stability and efficiency were synthesized by a facile electrospinning method. The proposed dynamic CeO2-mediated Sn0/Sn delta+ redox cycle mechanism improved formate selectivity during CO2 conversion. This work may provide a general strategy to design stable and efficient catalysts for practical CO2 electrolyzers.