No abstract

The photocatalytic decomposition of water is believed to be able to help mitigate the crisis of fossil fuel depletion.

A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Hydrogen produced by splitting water is receiving significant attention due to the rising global energy demand and growing climate concern. The photocatalytic decomposition of water converts solar energy into clean hydrogen, and may help mitigate the crisis of fossil fuel depletion. However, the photocatalytic hydrogen production remains challenging to obtain high and stable photoconversion efficiency. Here, we report a highly efficient photoanode based on coaxial heterogeneous cascade structure of Cu 2 Se/CdSe/TiO 2 synthesized via a simple room-temperature and low-cost electrochemical deposition method. The microstructure and composition of the Cu 2 Se top layer are regulated and controlled by doping Cu with various amounts in different zones of the CdSe/TiO 2 coaxial heterojunction and then using a simple integral annealing process. Surprisingly, a little effort made to achieve the Cu 2 Se top layer utilizing such doped CdSe/TiO 2 exhibits a significant enhancement in photocatalytic activity.The maximum stable photocurrent density of the sample with the optimal copper zone and doping concentration has reached up to 28 mA/cm 2 , which can be attributed to the success in the uniform dispersion of the three-layer heterogeneous nanojunctions among the anatase nanotube wall from top to bottom. This results in a stepwise structure of band-edge levels in the Cu 2 Se/CdSe/TiO 2 photoelectrode that is conducive to enhancing effectively the separation of the photogenerated electron-hole pair.