Carbon inserted defect-rich MoS2-X nanosheets@CdSnanospheres for efficient photocatalytic hydrogen evolution under visible light irradiation.

Carbon -MoS2-x@CdS (C-MoS2-x@CdS) core-shell nanostructures with controlled surface sulfur (S) vacancies were prepared via a glucose assisted hydrothermal growth method. The glucose acted as a reducing agent of C-MoS2-X to partially reduce Mo4+ ions to Mo3+ and served as a carbon source to insert the amorphous carbon into the layered MoS2-X simultaneously. The presence of Mo3+ result in the surface S-vacancies, which can provide more additional active sites and enhance the photocatalytic performance. Moreover, the inserted carbon in layered MoS2-X enhanced the electron mobility and decreased the resistance electron transfer. Density functional theory (DFT) calculation confirmed that the surface S-vacancies and the amorphous carbon increase the projected density of states at the conduct band edge, which could enhance the photo-absorption and photo-responsibility. The result is consistent with the photocatalytic H2 production experiment. C2-10%MoS2-x@CdS presented a high H2 evolution rate of 61,494 µmol h-1 g-1 under visible light irrigation (λ ≥ 420 nm), which is 1.98 times and 158 times higher than that of sample without S-vacancies (10%MoS2@CdS) and pure CdS, respectively.