CdS Photocorrosion Protection by MoSe2 Modification for Photocatalytic Hydrogen Production

As a promising and low-cost semiconductor photocatalyst, CdS can be excited under visible-light-driven and it has attracted extensive attention. In order to effectively avoid CdS photocorrosion, MoSe2/CdS composite is fabricated by mean of a special method. The MoSe2/CdS composite exhibits high photo-catalytic activity and stability, when the loading of MoSe2 is 5%, the H2-evolution yield of MoSe2/CdS composite photocatalyst reach 112.4 μmol h−1 under visible light irradiation, which is 4.94 times of pure CdS. In addition, the more detailed studies show that the improvement of photocatalytic activity and stability is due to the following reasons: it can be clearly found from the results of the UV–Visible diffuse reflectance spectrum that MoSe2 in MoSe2/CdS composite greatly improves the light absorption performance,which effectively increases the light absorption intensity of the MoSe2/CdS composite photocatalyst in the photocatalytic reaction system and promotes the electronic transition of the MoSe2/CdS composite photocatalyst. In addition, due to the excellent electron-transfer ability of MoSe2, the rapid transfer of photo-generated charges is further promoted, and the recombination of electron–hole pairs is effectively reduced, thereby MoSe2/CdS catalysts can provide more active sites for hydrogen evolution reaction. Moreover, the MoSe2/CdS composite photocatalyst shows higher photocurrent response, lower overpotential, faster electron transfer rate constant (KET) (3.33 × 108 s−1) and shorter fluorescence lifetime (2.52 ns) than pure CdS and pure MoSe2 because of the effective interface-electron transfer. The MoSe2/CdS composite photocatalyst effectively hinder the photoetching of CdS and achieves high photo-catalytic stability. And the possible mechanism of H2-evolution for MoSe2/CdS is proposed.