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

Hollow nanotubes covered by dense nanorods of SnCo-HNT were developed with strong electronic effects and exhibited excellent performance for CO 2 electroreduction toward C1 products with >90% Faradaic efficiencies over a wide potential range. Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO 2 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 V RHE to −1.2 V RHE , 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 Co 2+ and Co 3+ 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 CO 2 electroreduction. This study could provide a new strategy for the construction of oxide-derived catalysts for CO 2 electroreduction.