Two-dimensional SnS2/ZrSi2N4 van der Waals heterojunction as a spontaneously enhanced hydrogen evolution photocatalyst

Ying Hu, Feilong Xiong, Chaoyi Xin, Ying Wang, Zhengquan Li, Kai Wu Luo, Kejun Dong, Liang Xu

Research output: Contribution to journalArticlepeer-review

Abstract

Photocatalytic water splitting driven by photon excitation is a promising method for generating clean energy. This study focuses on designing a two-dimensional van der Waals heterojunction photocatalyst, created by vertically stacking SnS2 and ZrSi2N4. The intrinsic mechanisms and hydrogen evolution potential of this system were systematically investigated using first-principles calculations. The results demonstrate that the SnS2/ZrSi2N4 heterojunction is a type II heterojunction with an indirect band gap, and the staggered energy bands effectively separate the photogenerated carriers and enhance photocatalytic efficiency. Additionally, the near-ideal band gap of 2.30 eV ensures good light absorption while providing sufficient driving force for water decomposition. The band-edge positions of the heterojunction span the redox potential of water, which means that, in aqueous solutions with a pH range of 0–4, the external potential generated by photogenerated electrons is adequate to spontaneously drive hydrogen evolution through water splitting. Simultaneously, the Gibbs free energy (ΔG = −0.11 eV) being close to zero indicates that this heterojunction can effectively facilitate the hydrogen evolution reaction (HER). Furthermore, the exceptional electron mobility (2048.38 cm2·V−1·S−1), hole mobility (4299.49 cm2·V−1·S−1), and solar-to-hydrogen conversion efficiency of up to 17.92 % underscore its immense potential as an effective photocatalyst. This work offers innovative approaches for achieving efficient photocatalytic water decomposition, advancing the development of clean energy solutions.

Original languageEnglish
Article number110816
Number of pages10
JournalMaterials Today Communications
Volume41
DOIs
Publication statusPublished - Dec 2024

Bibliographical note

Publisher Copyright:
© 2024 Elsevier Ltd

Keywords

  • First principle calculations
  • Hydrogen evolution
  • Photocatalysis
  • SnS/ZrSiN heterojunction
  • Spontaneous reaction

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