Graphene decorated MoS2 for eosin Y-sensitized hydrogen evolution from water under visible light

Some two-dimensional nanomaterials, such as graphene and molybdenum disulfide, are presently being intensively investigated due to their excellent and unique performances. In the field of photocatalysis, MoS2 is considered as a promising alternative to noble metal Pt for the hydrogen evolution reaction (HER). However, its poor electrical conductivity restricts its catalytic activity in the HER. In this work, MoS2 was modified with graphene (G) by a simple hydrothermal method. The prepared G/MoS2 composite was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results show that graphene modification does not influence the crystal phase of MoS2, but makes the latter more dispersed. The HER performance of G/MoS2 was evaluated using eosin Y (EY) as a photosensitizer, and triethanolamine (TEOA) as a sacrificial electron donor under visible-light irradiation (lambda > 420 nm, 250 W high pressure Hg lamp as light source). The EY sensitized G/MoS2 composite displays enhanced hydrogen evolution in terms of not only activity but also stability. The average HER activity (9.1 mu mol h(-1)) is three times that of EY sensitized pure MoS2 over 10 h. It is believed that the incorporation of graphene enhances the charge transfer ability and retards the self-degradation path of EY center dot-, ultimately improving the HER.