Engineering tandem catalysts and reactors for promoting electrocatalytic CO2 reduction reaction toward multi-carbon products

Electrocatalytic CO2 reduction reaction (eCO2RR) is one of the most promising pathways to alleviate the global greenhouse effects while simultaneously producing value-added chemicals. In recent years, multi-carbon (C2+) products synthesized by eCO2RR have attracted increasing attention because of their high energy density and a broad range of practical usage. Unfortunately, the selectivity, stability, and energy efficiency of eCO2RR for achieving single C2+ product are still far too low to meet the standards of industrial production. The tandem CO2 electrocatalysis has demonstrated promising potential to boost the formation of C2+ products, in which the C-C coupling energy barrier could be efficiently decreased through the enrichment of intermediates. However, solely focusing on the design of tandem elec-trocatalysts is insufficient to produce long-chain hydrocarbons in a large scale. Herein, this review summarizes, in addition to the comprehensive analysis of the recent fine design of tandem CO2 electrocatalysts, the latest research progress of tandem reactors for the eCO2RR. The current problems, potential solutions and perspective development directions of CO2 tandem electrolysis in the future are also discussed. It aims to provide a fundamental springboard for improving the selectivity of C2+ products and, more importantly, push forward the ultimate performance for reaching industrial synthesis of C2+ products.