Abstract
Hydrogen (H2) evolution reaction from photoreduction of water is a technology that converts solar energy into chemical fuel by charge carriers (electron-hole pairs) in semiconductor photocatalysts under sunlight illumination, which has been received considerable attention in the development of renewable energy. In this study, aspect ratio (AR)-tunable CdSe/CdS dot-in-rod (DiR) nanoheterostructures (NHSs) were synthesized by hot injection method. The quasi-type Ⅱ band structure of CdSe/CdS DiR was confirmed by ultraviolet photoelectron spectroscopic characteristics. When the AR of CdSe/CdS DiR was tuned from 9.8 to 37.0, the exciton localization efficiency decreased from 57.9 % to 15.1 % and the H2 evolution rate enhanced from 0.40 to 2.11 mmol g-1 h-1. In-situ transient absorption spectroscopy was employed to study the interfacial charge carrier dynamics of CdSe/CdS DiRNSs during the photocatalytic H2 evolution. The results indicated that the half-life of photoexcited electrons in CdSe/CdS DiRNS increases from 11.5 μs to 20.1 μs as the AR increased. These outcomes suggest that the AR-dependent charge carrier dynamics dominates the efficiency of photocatalytic H2 evolution in CdSe/CdS DiR. This research provides the important and novel insights into the mechanism of semiconductor heterostructures for efficiency improvement in renewable energy generation.
Published Version
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