Surface Ligand Engineering in Quantum Dot Photocatalysis: Mechanisms, Design Principles, and Applications

ABSTRACT

Quantum dots (QDs) combine size‐tunable bandgap with strong light absorption, yet their photocatalytic efficiency is constrained by surface defects and insulating ligand shells that impede charge transfer. Surface ligand engineering has emerged as a core strategy to resolve this dilemma by simultaneously passivating trap states and reconstructing interfacial charge‐transport pathways. This review systematically surveys recent advances in ligand‐mediated regulation of QD photocatalysis, organized around three interconnected mechanistic levels: thermodynamic band‐edge tuning through interfacial dipoles, kinetic charge‐transfer control via exciton delocalization and barrier reduction, and microenvironmental regulation of surface reactions through local polarity and reactant accessibility. We discuss how different synthetic routes preset the initial surface state, compare solid‐phase versus liquid‐phase ligand exchange strategies, and highlight applications in solar fuel production, organic transformations, environmental remediation, and tandem catalysis. Finally, we identify critical challenges—operando characterization, computational modeling, stability, heavy‐metal‐free materials, scalability, and data‐driven design—that must be addressed to advance QD‐based photocatalysis toward practical deployment.