Confinement and interface engineering of CuSiO3 nanotubes for enhancing CO2 electroreduction to C2+ products

Electrochemical CO2 reduction (ECR) to C2+ products is an efficient method to accomplish intermittent energy storage and CO2 utilization. Developing high-selectivity electrocatalysts for C2+ products, especially C2+ alcohols, have attracted more attention but still remains a major challenge. Here, three kinds of short nanotube (<100 nm), long nanotube (>100 nm), and long nanotube-assembled hollow sphere CuSiO3 catalysts with different confined space are fabricated for boosting the ECR to produce C2+ products selectivity. Long CuSiO3 nanotubes exhibit a higher yield of C2+ alcohols (26.8 %) and more satisfactory Faraday efficiency (FE) of 69.5 % for C2+ products than short nanotubes and nanotube-assembled hollow spheres. The confinement effect of long CuSiO3 nanotubes is conducive to promoting the dimerization of the key reaction intermediate (*CO), inhibiting the diffusion of protons and the side-reaction hydrogen evolution reaction (HER). The formed Cu-0/Cu+ interfaces in CuSiO3 nanotubes promote the dimerization reactions of adsorbed *CO. The synergistic effect of nanotubes confinement and Cu-0/Cu+ interfaces facilitate the CC coupling reaction to C2+ products via ECR.