A hierarchically structured tin-cobalt composite with an enhanced electronic effect for high-performance CO2 electroreduction in a wide potential range

Abstract

Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO2 to C1 products, e.g., CO and formate. However, it is still difficult for Sn-based materials to obtain satisfactory performance at low-to-moderate overpotentials. Herein, a simple and facile electrospinning technique is utilized to prepare a composite of a bimetallic Sn-Co oxide/carbon matrix with a hollow nanotube structure (SnCo-HNT). SnCo-HNT can maintain > 90 % faradaic efficiencies for C1 products within a wide potential range from − 0.6 VRHE to − 1.2 VRHE, and a highest 94.1 % selectivity towards CO in an H-type cell. Moreover, a 91.2 % faradaic efficiency with a 241.3 mA cm−2 partial current density for C1 products could be achieved using a flow cell. According to theoretical calculations, the fusing of Sn/Co oxides on the carbon matrix accelerates electron transfer at the atomic level, causing electron deficiency of Sn centers and reversible variation between Co2+ and Co3+ centers. The synergistic effect of the Sn/Co composition improves the electron affinity of the catalyst surface, which is conducive to the adsorption and stabilization of key intermediates and eventually increases the catalytic activity in CO2 electroreduction. This study could provide a new strategy for the construction of oxide-derived catalysts for CO2 electroreduction.