New gallium chalcogenides/arsenene van der Waals heterostructures promising for photocatalytic water splitting |
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Authors: | Qiong Peng Zhonglu Guo Baisheng Sa Jian Zhou Zhimei Sun |
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Affiliation: | 1. School of Materials Science and Engineering, and Center for Integrated Computational Materials Science, International Research Institute for Multidisciplinary Science, Beihang University, Beijing, 100191, China;2. Multiscale Computational Materials Facility, Key Laboratory of Eco-materials Advanced Technology, College of Materials Science and Engineering, Fuzhou University, Fuzhou 350108, China |
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Abstract: | Single two-dimensional (2D) GaS and GaSe were studied as photocatalysts, yet the overall performance is limited by the low optical absorption and inefficient separation of photogenerated electron-hole pairs. Constructing van der Waals (vdW) heterostructures is an ideal way to overcome the deficiency of single 2D gallium chalcogenides. This work unravels that gallium chalcogenides/arsenene (GaX/As, X = S, Se) are the promising vdW heterostructures that show significantly improved photocatalytic performance by means of first-principles calculations. The GaX/As heterostructures possess suitable band alignment and bandgap satisfying the requirements for photocatalysts. Contrary to the pristine monolayers, the Se0.5GaS0.5/As and S0.5GaSe0.5/As heterostructures undergo indirect-direct bandgap transition by varying the interlayer distances; moreover, they exhibit high carrier mobility (~2000 cm2 V?1 s?1 for electrons) and transport anisotropy, efficiently facilitating the migration and separation of photogenerated electron-hole pairs. Finally, all GaX/As heterostructures show significantly enhanced optical absorption beyond the isolated GaX monolayers under visible-light irradiation. These extraordinary properties render GaX/As heterostructures as competitive photocatalysts for water splitting to produce hydrogen. |
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Keywords: | vdW heterostructures Photocatalytic water splitting Band structure engineering Enhanced optical absorption High carrier mobility |
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