Integration of ohmic junction and step-scheme heterojunction for enhanced photocatalysis

Wei Zhao; Siying Liu; Yun Liu; Shuo Yang; Benzhi Liu; Xuekun Hong; Junyu Shen; Cheng Sun

doi:10.1016/j.jcis.2023.09.158

Integration of ohmic junction and step-scheme heterojunction for enhanced photocatalysis

J Colloid Interface Sci. 2024 Jan 15;654(Pt A):134-149. doi: 10.1016/j.jcis.2023.09.158. Epub 2023 Sep 27.

Authors

Wei Zhao¹, Siying Liu², Yun Liu², Shuo Yang², Benzhi Liu³, Xuekun Hong², Junyu Shen⁴, Cheng Sun⁵

Affiliations

¹ School of Materials Engineering, Jiangsu Key Laboratory of Advanced Functional Materials, School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, China. Electronic address: zhaowei-1983@cslg.edu.cn.
² School of Materials Engineering, Jiangsu Key Laboratory of Advanced Functional Materials, School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, China.
³ School of Environmental Science and Engineering, Yancheng Institute of Technology, Yancheng, Jiangsu Province, China.
⁴ School of Materials Engineering, Jiangsu Key Laboratory of Advanced Functional Materials, School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, China. Electronic address: 201800083@cslg.edu.cn.
⁵ State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China. Electronic address: envidean@nju.edu.cn.

PMID: 37837850
DOI: 10.1016/j.jcis.2023.09.158

Abstract

A novel and efficient photocatalyst, Cu₂WS₄/MoS₂-Au plasmonic Step-scheme (S-scheme) heterojunction, was constructed for the first time and applied to remove environmental pollutants. Among all the prepared photocatalysts, the. Cu₂WS₄/MoS₂-Au-5 exhibited the highest catalytic activity with an 89.1% reduction efficiency for Cr⁶⁺ and a 98.7% oxidation efficiency for Benzophenone-1 (BP-1) under visible light irradiation. The Cu₂WS₄/MoS₂-Au photocatalyst exhibits stable performance and efficient photocatalytic activity due to effective charge separation, enhanced light absorption from localized surface plasmon resonance (LSPR) of gold nanoparticles, and the formation of an S-scheme heterojunction with strong oxidation-reduction capabilities. In addition, through analysis of experiments and theoretical calculations, it is speculated that the Cu₂WS₄/MoS₂-Au follows a typical S-scheme photogenerated carrier transferring mechanism, which is verified by the finite difference time domain simulation, the free radical quenching experiments, the electron paramagnetic resonance analysis and the simulated charge density distribution. More importantly, the simulations of the work function and charge density distribution confirm the built-in electric field and the ohmic junction have been established at the interfaces between the Cu₂WS₄ and MoS₂ (Cu₂WS₄/MoS₂) as well as the interface between MoS₂ and Au (MoS₂-Au), respectively. The built-in electric field and ohmic junction enable efficient separation of photogenerated electrons and holes, ensuring the superior catalytic oxidation and reduction activities of the Cu₂WS₄/MoS₂-Au photocatalyst. Finally, we propose a photocatalytic mechanism for the Cu₂WS₄/MoS₂-Au plasmonic S-scheme heterojunction based on experimental results and simulated calculations. The research results of this study are significance for the development of the plasmonic S-scheme photocatalytic system.

Keywords: Heterojunction; Ohmic junction; Photocatalysis; S-scheme.