Functionalized 0D-3D heterostructure with ameliorated charge separation kinetics enables efficient photocatalytic hydrogen evolution

The construction of heterojunctions with a rapid space charge separation mechanism is an effective means to improve the photocatalytic activity. In this work, QDs/NH2-MIL-101(Fe)-AP photocatalyst equipped with built-in electric field was rationally prepared by a molecular modification strategy. Electron-withdrawing effect of the pyridine ring facilitates the directional transfer of electrons from the internal part of NH2-MIL-101(Fe) to the heterojunction interface. Meanwhile, the electron self-driven effect incidental to the suitable conduction band positions of QDs and NH2-MIL-101(Fe)-AP, and the co-driving effect of electron transfer exerted by hydrogen bonding accelerate the electron enrichment in the conduction band of NH2-MIL-101(Fe)-AP. The photocatalytic hydrogen evolution results showed that QDs/NH2-MIL-101(Fe)-AP reached an optimum rate of 2991.0 µmol h−1 g−1. Moreover, fluorescence and electrochemical tests revealed that the significant increase in photocatalytic activity is attributed to the efficient spatial separation of the photoinduced charge carriers.