Organic-moiety-engineering on copper surface for carbon dioxide reduction.

Electrochemical conversion of carbon dioxide (CO2) into value-added products powered by sustainable electricity is considered as one of the most promising strategies for carbon neutrality. Among the products, hydrocarbons, especially ethylene and ethanol are the most desired species due to their wide industrial applications. Copper-based catalysts are currently the very limited option available for catalyzing the reduction of CO2 to multi-carbon products. How to enhance the selectivity and current density is the focus in both academia and industry. In recent years, some organic molecules, oligomers and polymers with well-defined structures have been applied and demonstrated to be effective on enhancing electrocatalytic activity of copper catalysts. However, the molecular/copper interaction and CO2 molecules' behavior at the hetero-interface remain unclear. In this review, we classify the different organic materials which have been applied in the field of electrochemical CO2 reduction. We focus on the regulation of local microenvironment on the copper surface by organic compounds, including surface hydrophobicity, local electric field, local pH, and coverage of intermediates etc. The relationship between local microenvironment and catalytic activity is specifically discussed. This review could provide guidance for the development of more organic/inorganic hybrid catalysts for further promoting CO2 reduction reaction.