Defect-rich copper phyllosilicate promotes electrochemical CO2 reduction to C2+ alcohols.

A central goal in designing catalysts for electrochemical CO2 reduction (CO2RR) is to achieve high selectivity towards multicarbon (C2+) products that can be used in fuel and fine chemical production. Copper has long been prioritized in CO2RR electrocatalyst development due to the ability of Cu+ species to enhance C2+ product formation. This work reports the synthesis of defect-rich copper phyllosilicate (CuPS, Cu2Si2O5(OH)3) that contains high Cu+ content, but no crystalline Cu2O, using a laser synthesis in liquid approach. This catalyst achieves good CO2RR selectivity toward ethanol and n-propanol, with faradaic efficiencies of 7.6% and 8.1%, respectively. Computational modeling shows that introducing oxygen vacancies through the removal of surface hydroxyl groups on the Cu2Si2O5(OH)3 chrysocolla phase promotes C-C coupling and suppresses formation of undesired C1 products. These findings suggest that imparting defects such as oxygen vacancies into CuPS can be a promising strategy to enhance selectivity toward C2+ alcohols in the CO2RR.