Electro- and Photocatalytic C─X Bond Coupling in Valorization of Waste Plastics/Biomass: Reaction Mechanism and...

Electro- and photocatalytic carbon─heteroatom (C─N/S) coupling has opened an emerging avenue for upgrading waste plastic/biomass-derived feedstocks into value-added nitrogen- and sulfur-containing chemicals, such as amides, amino acids, and organosulfur compounds. However, this process is hindered by complex reaction networks, competing side reactions, and unstable active sites, which compromise activity, selectivity, and long-term stability. Overcoming these challenges requires a fundamental understanding of catalytic mechanisms and rational catalyst design to achieve efficient substrate activation and optimized intermediate management. However, a systematic review specifically addressing the transformation of waste plastics/biomass into C─X compounds remains lacking to date. To fill this gap, this review summarizes recent advances in electro- and photocatalytic C─X coupling reactions for the valorization of waste plastics/biomass, focusing on the design of synergistic active sites, the control of reactive intermediates, mechanistic elucidations, and large-scale production design. Furthermore, we evaluate the economic feasibility and environmental benefits of such strategies through techno-economic analysis and life-cycle assessment. Finally, key challenges in process integration and scale-up are discussed, outlining future directions to advance these technologies toward practical implementation in a circular carbon economy.