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Improved Light Harvesting and Efficiency for Overall Water Splitting by Embedding TiO 2 Transition Layer in GaP/Ga 2 O 3 /Ga 2 Se 3 Multijunction Photocatalyst
Author(s) -
Wang Meng,
Lu Gongxuan
Publication year - 2021
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.202000619
Subject(s) - photocatalysis , water splitting , materials science , band gap , catalysis , visible spectrum , quantum efficiency , energy conversion efficiency , crystal (programming language) , photocatalytic water splitting , absorption (acoustics) , layer (electronics) , optoelectronics , photochemistry , nanotechnology , chemistry , composite material , biochemistry , computer science , programming language
Photocatalytic water splitting to generate hydrogen has attracted great attention due to its potential for conversion and storage of solar energy. To obtain high efficiency of water splitting under solar irradiation, the catalyst should have good enough absorption in the visible region, excellent charge transfer ability, and satisfied stability during the photoreaction. Herein, the significant absorption promotion of the catalyst to a longer wavelength is achieved by simultaneously in situ selenylation and phosphorization of Ga 2 O 3 . The formation of narrow‐bandgap Ga 2 Se 3 and GaP layers makes the catalyst absorb visible light up to 640 from 282 nm. In addition, by embedding a TiO 2 transition layer between Ga 2 O 3 and Ga 2 Se 3 , better crystal match in the catalyst is accomplished, which leads to better structural stability and the formation of better charge transfer route. Compared with GaP/Ga 2 O 3 /Ga 2 Se 3 , the GaP/TiO 2 /Ga 2 O 3 /TiO 2 /Ga 2 Se 3 photocatalyst exhibits a much higher photocatalytic H 2 evolution activity and achieves a higher apparent quantum efficiency (≈4% at 430 nm). Moreover, the TiO 2 transition layer also reduces the crystal mismatch between GaP and Ga 2 O 3 . Herein, the advantage of utilizing the transition layer in multijunction photocatalyst to increase the photocatalytic activity and strengthen the stability of the assembled catalyst for overall water splitting is demonstrated.