Effect of the oxidation state and morphology of SnOx-based electrocatalysts on the CO2 reduction reaction

Abstract

AbstractCO2 electrochemical reduction reaction (CO2RR) is an attractive strategy for closing the anthropogenic carbon cycle and storing intermittent renewable energy. Tin-based electrocatalysts exhibit remarkable properties for reducing CO2 into HCOOH. However, the effects of morphology and oxidation state of tin-based electrocatalysts on the performance of CO2 reduction have not been well-described. We evaluate the oxidation state and particle size of SnOx for CO2 reduction. SnOx was effective for converting CO2 into formic acid, reaching a maximum selectivity of 69%. The SnO exhibited high activity for CO2RR compared to SnO2 electrocatalysts. A pre-reduction step of a SnO2 electrocatalyst increased its CO2 reduction performance, confirming that Sn2+ is more active than Sn4+ sites. The microsized SnO2 is more effective for converting CO2 into formic acid than nanosized SnO2, likely due to the impurities of nanosized SnO2. We illuminated the role played by both SnOx particle size and oxidation state on CO2RR performance. Graphic abstract