Molybdenum carbide nanoparticles as a catalyst for the hydrogen evolution reaction and the effect of pH

• Mo2C nanoparticles on a carbon support were prepared with a soft carburization method.
• Mo2C nanoparticles were efficient for catalyzing the hydrogen evolution reaction.
• pH analysis was utilized to study the H2 evolution mechanism on Mo2C for the first time.
• The reaction mechanism at low pH leans toward the Volmer–Heyrovský mechanism.
• Mo2C nanoparticles retained their performance for four weeks of operation.

Molybdenum carbide nanoparticles supported on carbon catalysts have been prepared by a modified carbothermal reduction method. The soft carburization conditions of this method allow the preparation of nanoparticulate Mo2C even with a high Mo loading (50 wt.%). The catalytic activity for the hydrogen evolution reaction was analyzed both in an electrochemical cell at various pH and in a laboratory-scale electrolyzer. These nanoparticles were found to be very active in catalyzing hydrogen evolution reaction in acidic media and appeared to promote kinetics leaning toward the Volmer–Heyrovský mechanism at low pH. Moreover, the Mo2C/C catalyst was shown to be suitable for hydrogen production in a laboratory-scale electrolysis cell, retaining its performance during a four-week durability experiment. Thus this study implies that the investigated Mo2C/C electrocatalyst is a promising alternative to platinum as a cathode material for electrolytic hydrogen production because of its favorable kinetics and stability.

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