Theoretically Designed Cu10Sn3-Cu-SnOx as Three-Component Electrocatalyst for Efficient and Tunable CO2 Reduction to Syngas.

Electrocatalytic transformation of CO2 to various syngas compositions is an exceedingly attractive approach to carbon-neutral recycling. Meanwhile, the achievement of selectivity, stability, and tunability of product ratios using single-component electrocatalysts is challenging. Herein, the theoretically-assisted design of the triple-component nanocomposite electrocatalyst Cu10Sn3-Cu-SnOx that addresses this challenge is presented. It is shown that Cu10Sn3 is a valuable electrocatalyst for suitable CO2 reduction to CO, SnO2 for CO2 reduction to formate at large overpotentials, and that the Cu-SnO2 interface facilitates H2 evolution. Accordingly, the interaction between the three functional components affords tunable CO/H2 ratios, from 1:2 to 2:1, of the produced syngas by controlling the applied potentials and relative contents of functional components. The syngas generation is selective (Faradaic efficiency, FE = 100%) at relatively lower cathodic potentials, whereas formate is the only liquid product detected at relatively higher cathodic potentials. The theoretically guided design approach therefore provides a new opportunity to boost the selectivity and stability of CO2 reduction to tunable syngas.