This review highlights recent progress in photocatalytic CO₂ reduction toward multi-carbon products, emphasizing key advances in catalyst design. Strategies including atomic site dispersion, co-catalyst integration, defect engineering, and utilization of localized surface plasmon resonance (LSPR) are discussed to promote C–C coupling, offering insights into selective solar-to-chemical conversion.

Abstract

Photocatalytic CO₂ reduction represents a sustainable pathway for mitigating carbon emissions and producing renewable chemicals by utilizing solar energy. While extensive research has been dedicated to single-carbon (C₁) products, the selective formation of multi-carbon (C₂₊) compounds, such as ethylene, ethane, ethanol and acetic acid, has garnered increasing attention due to their higher energy density and broader industrial relevance. However, achieving efficient C─C coupling under mild photocatalytic conditions remains a formidable challenge, hindered by complex reaction pathways, sluggish kinetics and competitive side reactions. In this review, recent advances in photocatalytic CO₂ reduction to C₂₊ products was systematically summarized, focusing on fundamental reaction mechanisms, rational photocatalyst design strategies, including atomically dispersed active sites, cocatalyst loading, defect engineering, and localized surface plasmon resonance (LSPR). By bridging mechanistic understanding with materials innovation, this review provides a comprehensive framework for guiding the development of next-generation photocatalytic systems for efficient and selective CO₂-to-C₂₊ conversion, contributing to sustainable carbon utilization and circular chemical economy.