Molybdenum/graphene – Based catalyst for hydrogen evolution reaction synthesized by a rapid photothermal method

•A mixture of MoO2, sulfur and graphene has been prepared with natural sunlight.•XRD, SEM, EDX and FTIR validate material composition.•The high material surface area is advantageous for HER processes.•The material has favorable overpotential and Tafel slope values for catalysis.•The stability, activity, and green synthesis are favorable for clean energy.

Catalysis of the hydrogen evolution reaction (HER) is important in the development of an energy economy based on clean hydrogen gas. In this work, we report a new catalyst material for the generation of hydrogen via hydronium reduction. The new material, which consists of MoO2, sulfur, and graphene, was prepared by co-reduction of molybdenum salt and graphite oxide in air in the presence of focused solar radiation. The potential utility of this material for HER catalysis was evaluated by cyclic and linear-sweep voltammograms and compared against a Pt/C commercial catalyst. The MoO2/graphene hybrid nanocomposite exhibits a Tafel slope of 47 mV/dec and hydrogen evolution at a potential only ∼120 mV more negative than the standard Pt/Carbon catalyst at 10 mA/cm2 current density. The hydrogen gas generated by the catalytic material was measured using gas chromatography. The simple synthesis and low overpotential suggests that this hybrid composite has potential as an HER catalyst.

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