One-step preparation of molybdenum disulfide/graphene nano-catalysts through a simple co-exfoliation method for high-performance electrocatalytic hydrogen evolution reaction

Hypothesis Recently, molybdenum disulfide (MoS 2 ) as a new type of catalyst, has been used for hydrogen evolution . In order to overcome the shortcomings of MoS 2 , such as poor conductivity and lack of catalytic activity sites, various materials were added to prepare composites, such as graphene with good conductivity. Experiments In this work, we combined MoS 2 with graphene through a very simple liquid-phase salt-assisted co-exfoliation method. The obtained MoS 2 /graphene nano-composites have been further applied to electrocatalyst of hydrogen evolution reaction. The influences of different ratio of MoS 2 to graphene and different solvents of exfoliation on the electrocatalytic activity for the hydrogen evolution reaction have been investigated in detail. Findings In general, the obtained MoS 2 /graphene nano-catalysts exhibits the smallest Tafel slope of 61 mV/dec with the exfoliation solvent of isopropanol, and 65 mV/dec in N-methyl pyrrolidone. All the MoS 2 /graphene composites exhibit much better catalytic activity than either MoS 2 or graphene single substance due to the synergetic effect between MoS 2 and graphene nanosheets .