ZnO/CdSe-diethylenetriamine nanocomposite as a step-scheme photocatalyst for photocatalytic hydrogen evolution

摘要

ZnO/CdSe-diethylenetriamine (ZnO/CdSe-DETA) nanocomposites are synthesized by a two-step hydrothermal method. The content of CdSe-DETA in the nanocomposites has a significant effect on the photocatalytic activity of hydrogen evolution. Under the irradiation of a xenon lamp with a UV-cutoff filter (lambda = 420 nm), the nanocomposite with a CdSe-DETA content of 43.36% reaches a hydrogen evolution rate of 11.09 mol g(-1)h(-1), which is 4.32 and 123.22 times than that of CdSe-DETA and ZnO, respectively. The better photocatalytic hydrogen evolution activity of the ZnO/CdSe-DETA is due to several factors. DETA can be inserted into the interlayer of Cd-Se and form CdSe-DETA nanobelts with large specific surface area. The ZnO/CdSe-DETA nanocomposite has a wide range of light absorption. The step-scheme heterojunction formed between ZnO and CdSe-DETA can significantly enhance the separation and migration of photoinduced electrons and holes, thus improving the photocatalytic performances of the photocatalysts. The addition of Pt as a cocatalyst is helpful to the separation of electrons, and the absorption of visible light can be enhanced by the surface plasmon resonance effect of Pt. This work may be helpful to construct step-scheme photocatalytic systems with high photocatalytic activity for hydrogen evolution.