Metallic 1T-LixMoS2 Cocatalyst Significantly Enhanced the Photocatalytic H2 Evolution over Cd0.5Zn0.5S Nanocrystals under Visible Light Irradiation.

In the present work, metallic 1T-LixMoS2 is utilized as a novel cocatalyst for Cd0.5Zn0.5S photocatalyst. The obtained LixMoS2/Cd0.5Zn0.5S hybrids show excellent photocatalytic performance for H2 generation from aqueous solution containing Na2S and Na2SO3 under splitting visible light illumination (λ ≥ 420 nm) without precious metal cocatalysts. It turns out that a certain amount of intercalating Li(+) ions ultimately drives the transition of MoS2 crystal from semiconductor triagonal phase (2H phase) to metallic phase (1T phase). The distinct properties of 1T-LixMoS2 promote the efficient separation of photoexcited electrons and holes when used as cocatalyst for Cd0.5Zn0.5S photocatalyst. As compared to 2H-MoS2 nanosheets only having edge active sites, photoinduced electrons not only transfer to the edge sites of 1T-LixMoS2, but also to the plane active sites of 1T-LixMoS2 nanosheets. The content of LixMoS2 in hybrid photocatalysts influences the photocatalytic activity. The optimal 1T-LixMoS2 (1.0 wt %)/Cd0.5Zn0.5S nanojunctions display the best activity for hydrogen production, achieving a hydrogen evolution rate of 769.9 μmol h(-1), with no use of noble metal loading, which is about 3.5 times higher than that of sole Cd0.5Zn0.5S, and 2 times higher than that of 2H-MoS2 (1.0 wt %)/Cd0.5Zn0.5S samples. Our results demonstrate that Li(+)-intercalated MoS2 nanosheets with high conductivity, high densities of active sites, low cost, and environmental friendliness are a prominent H2 evolution cocatalyst that might substitute for noble metal for potential hydrogen energy applications.