High solar-to-hydrogen efficiency in a direct Z-scheme GaAs/GeH van der Waals heterostructure for photocatalytic water splitting
8 affiliations
- 1Faculty of Fundamental Sciences, Hanoi University of Industry 298 Cau Dien Hanoi 100000 Vietnam
- 2Division of Physics, School of Education, Dong Thap University Cao Lanh 870000 Vietnam
- 3Department of Materials Science and Engineering, Le Quy Don Technical University Hanoi 100000 Vietnam
- 4Center for Environmental Intelligence, VinUniversity Hanoi 100000 Vietnam
- 5School of Chemistry, Monash University Melbourne Victoria 3800 Australia
- 6New Industry Creation Hatchery Center (NICHe), Tohoku University Sendai 980-8579 Japan
- 7Department of Centre for Inter Disciplinary Research, SRM University-AP Amaravati 522240 Andhra Pradesh India
- 8College of Engineering and Computer Science, VinUniversity Hanoi 100000 Vietnam
Abstract
The development of efficient photocatalysts for solar-driven water splitting remains a critical challenge due to limited light absorption, rapid charge recombination, and insufficient redox capability. In this work, we propose a GaAs/GeH van der Waals (vdW) heterostructure and systematically investigate its structural, electronic, mechanical, optical, and photocatalytic properties using first-principles calculations. The results demonstrate that the heterostructure is energetically, mechanically, and dynamically stable and exhibits a direct band gap with a type-II band alignment, enabling effective spatial separation of photogenerated charge carriers. The GaAs/GeH heterostructure shows a reduced band gap and significantly enhanced optical absorption in the visible region. In addition, improved electron mobility is observed, which is beneficial for charge transport. Importantly, the band-edge positions are well aligned with the redox potentials of water, allowing both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to proceed. The system follows a direct Z-scheme charge transfer mechanism driven by an intrinsic built-in electric field, which preserves strong redox ability while suppressing carrier recombination. As a result, a theoretical solar-to-hydrogen (STH) conversion efficiency of 24.41% is achieved, demonstrating competitive photocatalytic performance compared with previously reported 2D heterostructures.These findings highlight the strong potential of the GaAs/GeH heterostructure for efficient solar-driven water splitting and provide valuable insights for the rational design of advanced photocatalytic materials.
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BibTeX
@article{nhan2026high,
title = {{High solar-to-hydrogen efficiency in a direct Z-scheme GaAs/GeH van der Waals heterostructure for photocatalytic water splitting}},
author = {Tran T. Nhan and Pham T. Truong and Le T. Ngoc Tu and Huynh V. Phuc and Chuong V. Nguyen and Ngoc-Trung Nguyen and Trang Minh Pham and Thi Kim Cuong Phu and Tam Duy Nguyen and Yoshiyuki Kawazoe and Thi Viet Bac Phung},
journal = {RSC advances},
year = {2026},
month = oct,
doi = {10.1039/d6ra08869d},
url = {https://europepmc.org/article/PMC/PMC13673663},
note = {CC BY},
}
RIS
TY - JOUR
TI - High solar-to-hydrogen efficiency in a direct Z-scheme GaAs/GeH van der Waals heterostructure for photocatalytic water splitting
AU - Tran T. Nhan
AU - Pham T. Truong
AU - Le T. Ngoc Tu
AU - Huynh V. Phuc
AU - Chuong V. Nguyen
AU - Ngoc-Trung Nguyen
AU - Trang Minh Pham
AU - Thi Kim Cuong Phu
AU - Tam Duy Nguyen
AU - Yoshiyuki Kawazoe
AU - Thi Viet Bac Phung
PY - 2026
DA - 2026/10/16
JO - RSC advances
DO - 10.1039/d6ra08869d
UR - https://europepmc.org/article/PMC/PMC13673663
AB - The development of efficient photocatalysts for solar-driven water splitting remains a critical challenge due to limited light absorption, rapid charge recombination, and insufficient redox capability. In this work, we propose a GaAs/GeH van der Waals (vdW) heterostructure and systematically investigate its structural, electronic, mechanical, optical, and photocatalytic properties using first-principles calculations. The results demonstrate that the heterostructure is energetically, mechanically, and dynamically stable and exhibits a direct band gap with a type-II band alignment, enabling effective spatial separation of photogenerated charge carriers. The GaAs/GeH heterostructure shows a reduced band gap and significantly enhanced optical absorption in the visible region. In addition, improved electron mobility is observed, which is beneficial for charge transport. Importantly, the band-edge positions are well aligned with the redox potentials of water, allowing both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to proceed. The system follows a direct Z-scheme charge transfer mechanism driven by an intrinsic built-in electric field, which preserves strong redox ability while suppressing carrier recombination. As a result, a theoretical solar-to-hydrogen (STH) conversion efficiency of 24.41% is achieved, demonstrating competitive photocatalytic performance compared with previously reported 2D heterostructures.These findings highlight the strong potential of the GaAs/GeH heterostructure for efficient solar-driven water splitting and provide valuable insights for the rational design of advanced photocatalytic materials.
SN - 2046-2069
ER -