Revealing the synergetic effects of graphene and MoS2 on boosted photocatalytic H2 production of Mn0.5Cd0.5S photocatalyst.

• A new ternary Mn 0.5 Cd 0.5 S/RGO-MoS 2 composite was successfully synthesized. • The synergetic effect between RGO and MoS 2 cocatalyst were discussed. • Mechanism of the enhanced photocatalytic activity was illuminated. A new solar-light-active ternary heterojunction photocatalyst, consisting of Mn 0.5 Cd 0.5 S nanoparticles grown on 2D reduced graphene oxide (RGO)-MoS 2 hybrid composite as a nonprecious and highly efficient cocatalyst has been successfully fabricated via a facile in-situ growth process. The optimized Mn 0.5 Cd 0.5 S/RGO-MoS 2 nanocomposite with 2 wt% RGO-MoS 2 cocatalyst displays the highest H 2 -evolution rate of 642.15 µmol h−1, which is about 3.75 times higher than bare Mn 0.5 Cd 0.5 S and far exceeding other composite photocatalysts, i.e., Mn 0.5 Cd 0.5 S/RGO, Mn 0.5 Cd 0.5 S/MoS 2 and noble Pt-modified Mn 0.5 Cd 0.5 S. It was revealed that the dramatically improved photoactivity of the ternary Mn 0.5 Cd 0.5 S/RGO-MoS 2 heterojunction photocatalyst was mainly originated from the positive cooperation between RGO and MoS 2 nanosheets. The RGO nanosheets with high conductivity could serve as an electron transport bridge to collect and transfer the photogenerated electrons effectively, while MoS 2 nanosheets with high electrocatalytic activity could act as an effective H 2 -evolution cocatalyst to facilitate the photoinduced electrons taking part in the hydrogen production reaction from water reduction, thus boosting the H 2 -evolution kinetics. More importantly, the RGO nanosheets could also lead to the downshift of the valence band (VB) of Mn 0.5 Cd 0.5 S, which was beneficial for the rapid oxidation of sacrificial agents and the interfacial charge transfer/separation, thereby helping to improve the photocatalytic performance. [ABSTRACT FROM AUTHOR]