Emerging Cu-Based Tandem Catalytic Systems for CO2 Electroreduction to Multi-Carbon Products

Conversion of carbon dioxide (CO2) to valuable chemicals and feedstocks through electrochemical reduction holds promise for achieving carbon neutrality and mitigating global warming. C2+ products are of interest due to their higher economic value. Since the CO2 to C2+ conversion process involves multiple steps, tandem catalytic strategies are commonly employed in the design of electrochemical CO2 reduction reaction (CO2RR) catalysts and systems/reactors. Among the diverse catalysts that are capable of reducing CO2 to CO, Cu stands out for more efficiently further converting CO to C2+ products. In this review, the emerging Cu-based tandem catalysts and their impact on CO2RR performance, focusing on three positional relationships are summarized. It delves into the integration of tandem catalytic strategies into membrane electrolyzers, utilizing catalyst-coated substrate (CCS) and catalyst-coated membrane (CCM) technologies. Several typical examples are presented to illustrate this integration. Finally, the challenges and prospects of applying tandem strategies in the development of CO2RR catalysts/systems, as well as their device-level implementation are indicated.