Transition metal-doped amorphous molybdenum sulfide/graphene ternary cocatalysts for excellent photocatalytic hydrogen evolution: Synergistic effect of transition metal and graphene

Abstract Though amorphous molybdenum sulfide (MoS x ) is considered a promising H 2 evolution cocatalyst, its intrinsic activity and charge transfer efficiency are still unsatisfactory. To overcome these drawbacks, transition metal-doped (Fe, Co, or Ni) amorphous MoS x /graphene ternary nanocomposites were designed and fabricated using a one-step solvothermal method. Their structure, morphology, and properties were characterized. The metal-doped MoS x nanoparticles were well distributed on the graphene sheets in the ternary composites. Metal doping greatly enhanced the intrinsic activity of amorphous MoS x , and the integration of graphene notably promoted the separation of photoinduced carriers. The photocatalytic H 2 evolution with amorphous MoS x as cocatalyst has been substantially improved under the synergistic effect of the transition metal and graphene. The H 2 evolution rate of Co-doped amorphous MoS x /graphene composites reached 11.45 mmol·h −1 ·g −1 at the Co:Mo molar ratio of 2:3, which is 64% higher than that of Co-doped MoS x , 21 times that of undoped MoS x /graphene, and 127 times that of pure MoS x . This study would supply an efficient strategy and a new vision for developing excellent noble-metal-free photocatalysts for photocatalytic hydrogen production.