Mo(S,O)/(Ce,Mo)(S,O) sulfo-oxide with heterovalent metal states for efficient visible-light-driven hydrogen evolution and pollutant reduction via in-situ generated protons

• Published in: International journal of hydrogen energy 2023-04, Vol.48 (29), p.10841-10858
• Main Authors: Abdeta, Adugna Boke, Wu, Qinhan, Kuo, Dong-Hau, Li, Ping, Zhang, Hanya, Huang, Ting, Zhang, Jubin, Mosisa, Mengistu Tadesse, Lin, Jinguo, Chen, Xiaoyun
• Format: Article
• Language: English
• Subjects: Heterovalent metal states; Hydrogen evolution; In-situ generated proton; Mo(S, O)/(Ce, Mo)(S,O) sulfo-oxide; Pollutants reduction
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2022.12.155

The existence of the heterovalent metal states and S doping into Ce–Mo bimetallic oxide improve the photocatalytic activity by generating oxygen vacancy and narrowing the bandgap for suitable water splitting. Spherical and plate likes heterostructure Mo(S,O)/(Ce,Mo)(S,O) sulfo-oxide catalysts with heterovalent metal states and oxygen vacancy defects were synthesized by co-precipitation method for photocatalytic hydrogen evolution reaction. Catalyst labeled as 1-CeMoOS with more oxygen vacancies and high Ce3+/(Ce3++Ce4+) ratio evolved 405.18 μmol/h H2 and achieved AQE of 13.72%, whereas reduced 76.43% 4-NP and 91.52% RhB by in-situ generated protons. S doping, oxygen vacancy creation, Ce and Mo heterovalent states have narrowed the bandgap by substituting oxygen with sulfur, promoted the photogenerated charge carriers' effective separation, and prolonged the lifetime of electrons. The oxygen vacancy formation with a subsequently partial Ce4+-to-Ce3+ conversion achieves CeMoOS catalysts with excellent PHER and provides a promising way to improve photocatalysts' visible light PHER activity. [Display omitted] •Mo(S,O)/(Ce,Mo)(S,O) sulfo-oxide with Ce4+/Ce3+ and Mo6+/Mo4+ states synthesized.•Ce4+/Ce3+ and Mo6+/Mo4+ redox cycle produces surface oxygen vacancy.•Introduced S in Mo metallic and Ce–Mo bimetallic oxide narrows the band gap.•Ce3+.→Ce4+ and Mo4+→Mo6+ electron transport facilitate fast transfer of e− for PHER.•PHER mechanism over Mo(S,O)/(Ce,Mo)(S, O) sulfo-oxide proposed and discussed.