Large-scale production of H2 by electrochemical water splitting is discerned as one of the most economical and viable approaches and designing Pt-less electrocatalysts remains at the forefront of this technology development. Herein, in situ transformation of metal-organic frameworks (MOF), impregnated with a molybdenum precursor, into a porous and rigid carbon support and molybdenum carbide (Mo2C) was demonstrated to fabricate highly active and stable β-Mo2C/C heterostructure for electrocatalytic H2 evolution. The two-step synthesis approach involved the impregnation of molybdenum source into frameworks of MOF (namely MIL-53(Al)) followed by nucleation and growth of Mo2C nanocrystals into confined porous texture through carburization. Characterization revealed the formation of mesoporous carbon embodied with crystalline nanoparticles of β-Mo2C (between 5 and 10 nm). A probable mechanism for the formation of Mo2C/C nanocomposite is proposed. The propensity of the catalyst was tested towards the electrocatalytic H2 evolution reaction (HER) under alkaline aqueous media (1 M KOH). The electrocatalyst showed a remarkable HER activity as compared to the benchmark electrocatalyst Pt/C and Mo2C/XC72 black catalysts at 10 mA cm-2 and stability for 20 h at the same current density. Electrochemical impedance spectroscopy results of Mo2C/C were construed by two time constants, porosity and charge transfer, and the HER reaction followed the Volmer-Heyrovsky mechanism.
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)