Photo-assisted synthesis of zinc-iron layered double hydroxides/TiO2 nanoarrays toward highly-efficient photoelectrochemical water splitting

A highly-matched semiconductor/cocatalyst is crucial to enhance the bulk charge separation and surface reaction kinetics of the photoelectrode in the solar water splitting system. In this work, well-aligned, hierarchical zinc-iron layered double hydroxide (LDH) is in situ synthesized on the surface...

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Bibliographic Details
Published inNano energy Vol. 33; pp. 21 - 28
Main Authors Zhang, Ruikang, Shao, Mingfei, Xu, Simin, Ning, Fanyu, Zhou, Lei, Wei, Min
Format Journal Article
LanguageEnglish
Published Elsevier Ltd 01.03.2017
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Summary:A highly-matched semiconductor/cocatalyst is crucial to enhance the bulk charge separation and surface reaction kinetics of the photoelectrode in the solar water splitting system. In this work, well-aligned, hierarchical zinc-iron layered double hydroxide (LDH) is in situ synthesized on the surface of TiO2 by a facile and effective photo-assisted electrodeposition (PED) method. An experimental-computational combination study reveals that the photogenerated holes of TiO2 tend to travel to ZnFe-LDH which enhances the bulk charge separation; while ZnFe-LDH acts as a cocatalyst which accelerates the surface water oxidation reaction. The resulting TiO2/ZnFe-LDH-PE photoanode exhibits a largely enhanced PEC performance: the photocurrent density at 1.0V vs. RHE is 2.29 and 1.31 times higher than that of the pristine TiO2 and TiO2/ZnFe-LDH-E (prepared by a conventional electrosynthesis method) photoanode, with 150mV and 50mV of negative shift for onset potential. This can be ascribed to the enhanced interface interaction and highly-matched band structure between ZnFe-LDH and TiO2. It is expected that this strategy can be extended to other heterostructures for advanced performance in the fields of energy conversion and storage. Well-aligned zinc-iron layered double hydroxide (ZnFe-LDH) has been in situ synthesized on the surface of TiO2 by the photo-assisted electrodeposition method. The highly-matched semiconductor (TiO2)/cocatalyst (ZnFe-LDH) system displays much enhanced efficiency in photoelectrochemical water splitting. [Display omitted] •TiO2/ZnFe-LDH photoanode is synthesized by photo-assisted electrodeposition of ZnFe-LDH on TiO2 nanoarrays.•The obtained TiO2/ZnFe-LDH photoanode exhibits largely promoted performances in the PEC water splitting.•This work demonstrates a strategy to modify the semiconductor photoanode.
ISSN:2211-2855
DOI:10.1016/j.nanoen.2017.01.020