Protecting the state of Cu clusters and nanoconfinement engineering over hollow mesoporous carbon spheres for electrocatalytical C-C coupling

Copper-based catalysts are widely used to adjust the activity and selectivity of CO2 electroreduction reactions (CO2RR). In this article, we choose to use hollow mesoporous carbon spheres (HMCS) to confine and protect Cu clusters to achieve high C2 selectivity. The electrocatalytic results show that when the amount of Cu clusters confined by HMCS reaches 20% (Cu/HMCS5-20%), the selectivity of C2 products reach 88.7% at − 1.0 V vs. RHE. In situ Fourier transform infrared spectroscopy (FTIRS) shows that Cu clusters confined and protected by HMCS is beneficial to the conversion of *CO to *CHO, while the nanocavities formed by HMCS can effectively confine the in situ formed *CHO carbon intermediates, which facilitates the C-C bond coupling to form C2H4 and C2H5OH. We proposes a method to improve the C2 selectivity of CO2RR and reduce the amount of Cu in CO2RR by using the confinement effect of HMCS.