Anionic Sulfur Quantum Dots as Reductive Photocatalysts via the Auger Process for Dehalogenation Reactions

Quantum dots (QDs) have garnered significant attention as promising photocatalysts due to their high extinction coefficients, small size, and large specific surface area. The Auger process can make them strong reductive photocatalysts, enhancing the redox capabilities of QDs. However, in reduction reactions, QDs typically require the protection of inert gases and the addition of extra reducing agents. In this study, we utilized metal-free sulfur quantum dots (SQDs) as photocatalysts to achieve dehalogenation reactions under ambient air conditions without the need for additional reducing agents. Due to the absence of strict reaction conditions, this reaction can be easily amplified in a continuous flow reactor. Mechanistic studies revealed that the Auger process occurred in SQDs, making them strong reductive photocatalysts. The presence of 1,4-dioxane and the formation of charge-transfer complexes play crucial roles in enhancing the robustness of SQDs.