Photo/electrochemical Carbon Dioxide Conversion into C 3+ Hydrocarbons: Reactivity and Selectivity

Producing high-value fuels and chemicals via photo/electrochemical CO2 reduction reaction (CO2RR) remains an attractive goal to mitigate the negative impact of CO2 emissions and provide a sustainable energy source. The large industrial scale is currently discriminated by the relatively low product selectivity (a high cost is expected for separating the products) and the activity. The selective CO2 reduction into higher-order multi-carbon products is desirable from the economic point of view. Yet, most of the reported electrocatalysts have produced C1 and C2 products; however, the production of C3 products is less common. Cu-based catalysts are the most documented systems to produce C3 products because of the exclusive C−C coupling ability of the Cu system. However, creating multi-carbon products on non-Cu catalysts is unfairly discussed. Growing the research activity on non-Cu catalysts will enrich the categories of alternative catalysts and propose more understanding of the CO2RR mechanism. This should guide the development of more creative catalysts with the optimum configuration for high activity and selectivity for high-value C3 products. The catalysts′ development progress, including metallic Cu, biphase, or bimetallic Cu, non-Cu-based catalysts, has been discussed in light of the catalyst activity and selectivity. Some insights on the reaction mechanism for the desired C3 product (most commonly, n-propanol) and other C3+ products are also discussed.