Mechanism and application of quantum dot modification for enhancing the photocatalytic reduction performance of carbon dioxide.

Photocatalytic CO2 reduction represents a promising pathway for converting greenhouse gases into valuable chemicals and solar fuels, yet its practical viability is severely limited by inefficient light absorption, rapid charge recombination, and weak surface activation. Semiconductor quantum dots (QDs) have emerged as revolutionary modifiers to address these bottlenecks, offering unique size-dependent bandgaps, ultrashort charge migration distances, and multiple exciton generation (MEG) capabilities. This review systematically summarizes the fundamental mechanisms and recent advances of QD-modified photocatalytic systems for CO2 reduction. Distinct from conventional reviews, we provide a critical evaluation and comparative analysis of the intrinsic trade-offs associated with QD integration. By critically comparing various QD systems and advanced interface engineering strategies, this paper emphasizes that QD modification is not a simple plug-and-play solution. Finally, we highlight future research directions focused on precise strain engineering, ultrafast charge extraction, and continuous-flow scale-up, aiming to guide the rational design of highly active and stable QD-based photocatalysts for industrial applications.