Sulfur Substitution and Defect Engineering in an Unfavored MnMoO4 Catalyst for Efficient Hydrogen Evolution under Visible Light

Qinhan Wu; Longyan Chen; Dong-Hau Kuo; Ping Li; Adugna Boke Abdeta; Osman Ahmed Zelekew; Jinguo Lin; Xiaoyun Chen

doi:10.1021/acsami.3c02205

Sulfur Substitution and Defect Engineering in an Unfavored MnMoO₄ Catalyst for Efficient Hydrogen Evolution under Visible Light

ACS Appl Mater Interfaces. 2023 May 10;15(18):22142-22156. doi: 10.1021/acsami.3c02205. Epub 2023 Apr 26.

Authors

Qinhan Wu¹, Longyan Chen¹, Dong-Hau Kuo², Ping Li¹, Adugna Boke Abdeta¹, Osman Ahmed Zelekew³, Jinguo Lin¹, Xiaoyun Chen¹

Affiliations

¹ College of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
² Department of Materials Science and Engineering & Graduate Institute of Energy and Sustainability Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
³ Department of Materials Science and Engineering, Adama Science and Technology University, Adama 1888, Ethiopia.

PMID: 37127405
DOI: 10.1021/acsami.3c02205

Abstract

A novel and nonstoichiometric Mn_1-xMo(S,O)_4-y oxysulfide catalyst with oxygen vacancies and a partial Mo⁶⁺-to-Mo⁴⁺ transition after the substitution of sulfur was synthesized for an efficient photocatalytic hydrogen evolution reaction (PHER). With appropriate sulfur substitution, a MnMoO₄ semiconductor with a wide band gap was converted to Mn_1-xMo(S,O)_4-y with a narrow gap and a suitable band position for PHER. MnMo oxysulfide of 50 mg achieved a high PHER rate of 415.8 μmol/h under visible light, an apparent quantum efficiency (AQE) of 4.31% at 420 nm, and a solar-to-hydrogen (STH) conversion efficiency of 1.28%. Oxygen vacancies (V_O) surrounded by low coordination metal atoms act as active reaction sites, which strengthen water adsorption and activation. Here, we demonstrate that sulfur substitution of MnMoO₄ for lowering its wide band gap can not only disturb the strict periodicity of the lattice but also the valence states of Mn and Mo for enhancing PHER via material design.

Keywords: defect engineering; hydrogen evolution reaction; oxygen vacancy; oxysulfide catalyst; sulfur substitution.