Efficient electrochemical reduction of CO2 promoted by the electrospun Cu1.96S/Cu tandem catalyst.

Coupled with renewable electricity, electrochemical reduction of CO2 (CO2RR) is one of the sustainable strategies for the production of value-added carbon-containing chemicals. Cu-based catalysts are by far the most widely studied electrocatalytic materials for CO2RR, although they exhibit poor performance in CO selectivity. In this work, we have designed a Cu1.96S/Cu tandem structure via a combined electrospinning and calcination method. The catalyst enables CO2 reduction to CO with high selectivity >80% with a production rate of 34.6 μmol h-1 cm-2 at -0.68 V vs. RHE, which is superior to most of the Cu-based catalysts under the same operation conditions. Theoretical simulations show that the improved CO2RR performance stems from the Cu1.96S/Cu tandem structure in which Cu acts as a *CO-producing site and the neighboring Cu1.96S facilitates the following *CO desorption step. This work opens new possibilities for exploiting tandem catalysis mechanisms.