Modulation of the Band Bending of CdS by Fluorination to Facilitate Photoinduced Electron Transfer for Efficient H<sub>2</sub> Evolution over Pt/CdS
Jingyi Zhang, Pinglong Cai, Jun Lin
Abstract
The potential barrier (Schottky barrier), embodied in the upward band bending of an n-type semiconductor at the interface of a Pt-loaded semiconductor, often makes it difficult for the interfacial photoinduced electron transfer from the conduction band of the semiconductor to the loaded Pt, giving rise to the recombination probability of the photogenerated charges. In this work, we prepared fluorinated CdS by a facile hydrothermal process in the presence of NH4F. With the assistance of the noble metal Pt, the fluorinated CdS exhibits a superior photocatalytic H2 evolution to pristine CdS. Various characterization results revealed that the incorporation of the fluorine anions into the CdS lattice by fluorination apparently lowers the Fermi level to weaken the upward band bending of CdS at the Pt/CdS interface, favoring the interfacial photoinduced electron transfer from the conduction band of CdS to the loaded Pt for an efficient H2 evolution. This work highlights the role of weakening the potential barrier at the Pt/CdS interface in promoting the interfacial photoinduced electron transfer for efficient H2 evolution.