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

Electrocatalytic reduction of CO 2 to formate has become one way to increase the value of CO 2 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 CO 2 reduction reaction to formate on a tin(IV) oxide/zinc oxide (SnO 2 /ZnO) composite electrocatalyst with a grainy hollow nanofiber (HNF) structure. The faradaic efficiency (FE) of formate on the SnO 2 /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 SnO 2 /ZnO HNF exhibits 2 times and 4 times higher current density for formate generation than those of SnO 2 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 SnO 2 and ZnO, which facilitate faster electron transfer and improve the conductivity of SnO 2 /ZnO composite HNF.