Tuning Structures and Microenvironments of Cu-Based Catalysts for Sustainable CO2 and CO Electroreduction

ConspectusThe carbon balance has been disrupted by the widespread use of fossil fuels and subsequent excessive emissions of carbon dioxide (CO2), which has become an increasingly critical environmental challenge for human society. The production and use of renewable energy sources and/or chemicals have been proposed as important strategies to reduce emissions, of which the electrochemical CO2 (or CO) reduction reaction (CO2RR/CORR) in the aqueous systems represents a promising approach.Benefitted by the capacity of manufacturing high-value-added products (e.g., ethylene, ethanol, formic acid, etc.) with a net-zero carbon emission, copper-based CO2RR/CORR powered by sustainable electricity is regarded as a potential candidate for carbon neutrality. However, the diversity of selectivities in copper-based systems poses a great challenge to the research in this field and sets a great obstacle for future industrialization.To date, scientists have revealed that the electrocatalyst design and preparation play a significant role in achieving efficient and selective CO2-to-chemical (or CO-to-chemical) conversion. Although substantial efforts have been dedicated to the catalyst preparation and corresponding electrosynthesis of sustainable chemicals from CO2/CO so far, most of them are still derived from empirical or random searches, which are relatively inefficient and cost-intensive. Most of the mechanism studies have suggested that both intrinsic properties (such as electron states) and extrinsic environmental factors (such as surface energy) of a catalyst can significantly alter catalytic performance. Thus, these two topics are mainly discussed for copper-based catalyst developments in this Account.Here, we provided a concise and comprehensive introduction to the well-established strategies employed for the design of copper-based electrocatalysts for CO2RR/CORR. We used several examples from our research group, as well as representative studies of other research groups in this field during the recent five years, with the perspectives of tuning local electron states, regulating alloy phases, modifying interfacial coverages, and adjusting other interfacial microenvironments (e.g., molecule modification or surface energy). Finally, we employed the techno-economic assessment with a viewpoint on the future application of CO2/CO electroreduction in manufacturing sustainable chemicals. Our study indicates that when carbon price is taken into account, the electrocatalytic CO2-to-chemical conversion can be more market-competitive, and several potential value-added products including formate, methanol, ethylene, and ethanol can all make profits under optimal operating conditions. Moreover, a downstream module employing traditional chemical industrial processes (e.g., thermal polymerization, catalytic hydrolysis, or condensation process) will also make the whole electrolysis system profitable in the future. These design principles, combined with the recent advances in the development of efficient copper-based electrocatalysts, may provide a low-cost and long-lasting catalytic system for a profitable industrial-scale CO2RR in the future.