Tandem electrocatalysts for CO₂ reduction to prepare multi-carbon products

Electrocatalytic CO₂ reduction reaction (CRR) is considered as a sustainable approach to converting CO₂ into high value-added chemicals, assisting the goal of carbon peaking and carbon neutrality. Electrochemical CRR can be easily regulated by controlling the electrocatalyst, electrolyte, and reactor to produce various chemicals. Among different products, multi-carbon (C₂₊) products draw widespread attention for their high energy density and value along with complex reaction mechanisms. It is well recognized that *CO intermediate plays vital role in forming C₂₊ products and Cu is the only metal catalyst which can efficiently electro-reduce CO₂ to C₂₊ products. Therefore, researchers developed many strategies to increase the amount of *CO intermediate and further enhance the performance of C₂₊ products. Recently, designing tandem electrocatalysts consisted of Cu and the materials which can convert CO₂ to *CO intermediate has become a hotspot and achieved great achievements. In this review, we will summary the recent progress in tandem electrocatalysts for CO₂ reduction to prepare C₂₊ products, including the origin and fundamental mechanism of tandem electrocatalysis, the strategies of catalyst design, and regulation principles. In addition, some newest findings, like Cu tandem catalysts can achieve to produce C₂₊ products, are well introduced. Finally, the remaining challenges and prospects for future development are also proposed.