Rational Design of Photocatalysts for CO2 Reduction to Multi-Carbon Products

Photocatalytic reduction of CO2 into multi-carbon (C2+) products is a promising but challenging pathway for carbon recycling, primarily hindered by the high kinetic barrier of C–C coupling and inefficient charge dynamics. This review systematically elaborates on the recent advances in photocatalyst development, focusing on key material systems including metal oxides, sulfides, Cu-based materials, graphitic carbon nitride, metal organic frameworks, and covalent-organic frameworks. It highlights the structure-activity relationships within these materials that govern the reaction pathway and selectivity. Furthermore, a systematic evaluation of performance-enhancing strategies, including defect engineering, doping engineering, heterojunction construction, and plasmonic effects, highlights their ability to precisely modulate electronic structures and reaction microenvironments, thereby promoting efficient C–C coupling. Finally, this review provides a critical discussion of current limitations and future research frontiers, offering perspectives on product verification, in-situ mechanistic studies, bifunctional synergy, and reactor design for practical application.