All-Inorganic InP/ZnSe/ZnS Quantum Dots with Chalcogenidometallate Ligands for Biosolar Catalysis

Abstract

Core/shell quantum dots (QDs) are promising photocatalysts due to their exceptional light-harvesting capabilities. While shell passivation mitigates surface defects and improves chemical stability, it hinders the charge transfer to reactants and restricts photocatalytic properties. This study presents a strategy to overcome this limitation through ligand-induced band offset engineering (LBOE) using molecular metal chalcogenide complex (MCC) ligands, specifically thiostannate (Sn2S64-), onto the surface of InP/ZnSe/ZnS QDs. The MCC ligands reduce the energy barrier imposed by the ZnSe/ZnS shell via LBOE. This relaxation of the energy barrier helps overcome the quantum confinement effect-the limitation of conventional type-I core/shell QDs when applied as photocatalysts-thereby facilitating efficient charge transfer. As a result, it promotes the two-electron oxygen reduction reaction under light illumination, leading to significantly enhanced H2O2 generation. Leveraging this improved photocatalytic capability, MCC-functionalized QDs are integrated into a photoenzymatic cascade, ensuring continuous and stable in situ H2O2 production and consumption while driving enantioselective oxyfunctionalization reactions. This system achieves a record-high total turnover number of 173 000 over 12 hours, operating without the need for external sacrificial electron donors. The findings highlight the potential of MCC ligands in redefining the performance of QD photocatalysts, expanding their applicability in photobiocatalysis and beyond.