Cu-based materials for electrocatalytic CO2 to alcohols: Reaction mechanism, catalyst categories, and regulation strategies

Electrocatalytic CO2 reduction reaction (CO2RR) technology, which enables carbon capture storage and resource utilization by reducing CO2 to valuable chemicals or fuels, has become a global research hotspot in recent decades. Among the many products of CO2RR (carbon monoxide, acids, aldehydes and alcohols, olefins, etc.), alcohols (methanol, ethanol, propanol, etc.) have a higher market value and energy density, but it is also more difficult to produce. Copper is known to be effective in catalyzing CO2 to high value-added alcohols, but with poor selectivity. The progress of Cu-based catalysts for the selective generation of alcohols, including copper oxides, bimetals, single atoms and composites is reviewed. Meanwhile, to improve Cu-based catalyst activity and modulate product selectivity, the modulation strategies are straighten out, including morphological regulation, crystalline surface, oxidation state, as well as elemental doping and defect engineering. Based on the research progress of electrocatalytic CO2 reduction for alcohol production on Cu-based materials, the reaction pathways and the key intermediates of the electrocatalytic CO2RR to methanol, ethanol and propanol are summarized. Finally, the problems of traditional electrocatalytic CO2RR are introduced, and the future applications of machine learning and theoretical calculations are prospected. An in-depth discussion and a comprehensive review of the reaction mechanism, catalyst types and regulation strategies were carried out with a view to promoting the development of electrocatalytic CO2RR to alcohols.