In situ sulfuration synthesis of heterostructure MoS2–Mo2C@C for boosting the photocatalytic H2 production activity of TiO2

Abstract

Hexagonal molybdenum carbide (Mo₂C) with a similar structure to Pt as a cocatalyst has been extensively researched in the field of photocatalytic hydrogen evolution. However, owing to its limited hydrogen-evolution active sites, Mo₂C-modified photocatalysts always possess a relatively poor hydrogen evolution rate. Considering that the unsaturated sulfur atoms of MoS₂ easily adsorb H⁺ ions as hydrogen-evolution active sites, in this study, MoS₂ was introduced into Mo₂C@C to generate heterostructure MoS₂–Mo₂C@C for enhancing the photocatalytic hydrogen-production performance of TiO₂. The heterostructure MoS₂–Mo₂C@C nanoparticles by the in situ sulfuration of Mo₂C under high temperature were modified on the TiO₂ surface through a simple sonication method. The experimental results showed that the maximum hydrogen-production rate of MoS₂–Mo₂C@C/TiO₂ achieved 1160 μmol h⁻¹ g⁻¹ (AQE = 3.48%), which was 116, 1.9, and 3.9 times higher than that of TiO₂, Mo₂C@C/TiO₂, and MoS₂@C/TiO₂, respectively. The enhanced activity of MoS₂–Mo₂C@C/TiO₂ is ascribed to the fact that the more unsaturated S atoms of MoS₂–Mo₂C@C, as hydrogen-generation active centers in addition to Mo sites, can efficiently adsorb H⁺ ions to enhance the hydrogen-production rate. This work provides a novel path for designing the heterostructure cocatalysts in the photocatalytic H₂-evolution field.