Coupling Reaction in Electrosynthesis: Design Principles, Reaction Mechanisms and Catalyst Engineering

Coupling reaction is an effective strategy in the electrosynthesis field, benefiting from its clean energy resources and capacity to enrich the product category. Diverse coupling strategies have been designed to produce value-added chemicals from wastes (plastic, biomass, etc.); however, they still face difficulties including multi-intermediate adsorption and activation, complex catalytic mechanisms, as well as novel reaction design. A fundamental understanding of reaction mechanisms and catalyst design to achieve efficient coupling reaction is essential but remains lacking to date. To fill this gap, this review for the first time summarizes the recent advances of coupling reactions in electrosynthesis, emphasizing design principles for constructing multiple high-valued compounds, reaction mechanisms of different pathways and catalyst engineering to simultaneously catalyze various reactants. We also discussed their applications and scale-up productions in detail combining techno-economic analysis (TEA) and life cycle assessment (LCA), presenting electrolyzer upgrade methods and practical waste recycling routes of the frontier studies. Finally, we presented the existing challenges in this area and future directions in developing more integrated processes and high-performance catalysts to meet industrial needs. This review aims to provide theoretical insights for constructing coupling reactions and inspire innovative ideas to achieve efficient chemical electrosynthesis.