How to enhance the C2 products selectivity of copper-based catalysts towards electrochemical CO2 reduction?—A review.

This review makes a comprehensive summary of improving the selectivity of electrocatalytic CO 2 reduction to C 2 products, including the optimisation of catalysts, electrolytes and electrolytic cells. [Display omitted] Reducing the consumption of fossil fuels and improving the utilization of carbon dioxide (CO 2) are urgently needed to mitigate the effect of increasing CO 2 concentration in the atmosphere, which has led to global temperature rising and climate change. Electrochemical CO 2 reduction (ECR) is a promising strategy for converting CO 2 into high-value-added multi-carbon compounds (such as ethylene:C 2 H 4 and ethanol: C 2 H 5 OH) through proton coupled electron transfer (PCET) steps, in which copper (Cu) is to date the only metal that can promote C–C coupling to produce C 2 products in aqueous solutions. However, due to the inherent moderate adsorption capacity of Cu on carbon-containing small molecule groups and the variety of C 2 products intermediates, low product selectivity remains the dominant drawback of metal Cu-based catalysts. A large number of strategies have been investigated to optimize the distribution of electrolysis products, including alloying, anion and cation species regulation, facet design, and tandem catalysis. In this review, we first elaborate the reaction mechanism of C 2 products generation on Cu-based catalysts, aiming to provide guidance for designing more selective catalysts. Then, with the intention of providing new insights into improving C 2 olefins and oxides, we summarize the aspects, including catalysts, electrolytes microenvironment, electrolyzer design, and other factors that affect the selectivity of C 2 products in catalytic systems. Finally, the main challenges and prospects for the future of Cu-based catalytic systems are outlined. The review is expected to stimulate more extensive studies on highly selective electrocatalysts of C 2 products by ECR. [ABSTRACT FROM AUTHOR]