Highly efficient photoanodes based on cascade structural semiconductors of Cu₂Se/CdSe/TiO₂: a multifaceted approach to achieving microstructural and compositional control

Abstract

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.

Compound Copper Chalcogenide Nanocrystals

“…Interestingly, Tan et al used Cu/CuS-ZnO/ZnS branched nanowires for PEC water splitting and observed that sonication provided higher photocurrent densities, which was due to a self-bias associated with the piezoelectric voltage created at the ZnO . A wide range of viable constructs is possible with, for example, Chong et al reporting the high performance of TiO 2 /CdSe/Cu 2 Se cascade architecture on a TiO 2 nanotube array structure (as photoanodes), where stable photocurrent densities of up to 20 mA cm −2 were demonstrated …”

Surface Engineering of Anodic WO3 Layers by In Situ Doping for Light-Assisted Water Splitting

“…Photoelectrochemical (PEC) water splitting under solar radiation is considered a promising strategy for producing hydrogen gas, which can serve as a highly energy-dense fuel with clean combustion byproducts . These systems rely on efficient and stable photoelectrodes, with the predominant focus in the field aimed at addressing low efficiency, limited long-term stability, and applicability restricted to the ultraviolet radiation region. − Anodic metal oxides show promise for this purpose due to their unique geometry, , relatively high surface area, and properties such as light absorption ability and generation of charge carriers under illumination . Furthermore, photoelectrodes based on anodic oxides do not require elaborate preparation because of the relatively good adhesion between the porous film and a conductive metal, as well as its perpendicular orientation to the substrate, which facilitates an efficient electron transfer path .…”

Hierarchical Co0.85Se‐CdSe/MoSe2/CdSe Sandwich‐Like Heterostructured Cages for Efficient Photocatalytic CO2 Reduction

“…[ 6 ] Nevertheless, the photocorrosion problem is an inherent drawback of metal selenides. [ 7 ] It is, therefore, vital to inhibit photocorrosion via advanced surface engineering methods. The addition of carbon coating has been proved to be effective in inhibiting the photocorrosion.…”