SnO2/ZnO Composite Hollow Nanofiber Electrocatalyst for Efficient CO2 Reduction to Formate

Electrocatalytic reduction of CO2 to formate has become one way to increase the value of CO2 and to overcome the climate change issue. Novel catalysts for the critical role of enhancing reaction selectivity have been continuously explored to provide the best performance. Lately, composite materials have drawn much attention because the synergistic effect between the components provides enhanced physical and chemical properties. Here, we present a highly efficient CO2 reduction reaction to formate on a tin­(IV) oxide/zinc oxide (SnO2/ZnO) composite electrocatalyst with a grainy hollow nanofiber (HNF) structure. The faradaic efficiency (FE) of formate on the SnO2/ZnO composite HNF reaches as high as 97.9% at −1.34 V vs reversible hydrogen electrode (RHE), outperforming many tin-based catalysts. At −1.54 V (vs RHE), the SnO2/ZnO HNF exhibits 2 times and 4 times higher current density for formate generation than those of SnO2 HNF and nanoparticles (NPs), respectively. This superior catalytic performance is attributed to its one-dimensional continuous structure as well as to the synergistic effects between SnO2 and ZnO, which facilitate faster electron transfer and improve the conductivity of SnO2/ZnO composite HNF.