Plasmonic MoO₂ as co-catalyst of MoS₂ for enhanced photocatalytic hydrogen evolution

Generally, photocatalytic water splitting on MoS₂ nanomaterials is restricted owing to the high carrier recombination and limited utilization of the visible light. This study describes the enhancement of the MoS₂-catalysed hydrogen evolution by incorporating metallic MoO₂ as a co-catalyst introduced by coupling with MoS₂ nanosheets through a facile calcination strategy, forming a Schottky junction between MoO₂ and MoS₂. The localized surface plasmon resonance effect induced by the oxygen vacancies and favourable Fermi lever position of MoO₂ lead to a broad spectral response and a significant improvement in the exciton generation and dissociation. The electron gets transferred from the conduction band (CB) of MoS₂ to MoO₂, wherein MoO₂ acts as an ‘electron pool’ that gathers the photoexcited electrons, which are rapidly shuttled to the surface of MoO₂, where the redox reaction occurs due to its great metallic conductivity. Resultantly, a 242% increment in the production of hydrogen gas by MoS₂/MoO₂ is achieved in comparison with that of the MoS₂ nanosheets.