Achieving enhanced electrocatalytic performance towards hydrogen evolution of molybdenum carbide via morphological control

Abstract The rational design of highly active electrocatalysts for hydrogen evolution reaction (HER) with controllable morphology creates new opportunities for future hydrogen economy. Herein, a facile strategy was developed to synthesize molybdenum carbide (Mo2C). First, Mo-based inorganic-organic complexes with distinct architectures were constructed by judiciously adjusting the pH values of the reaction systems as well as the types of inorganic and organic components. Next, the complexes were calcinated under vacuum to form different assemblies such as nanofibers, polyhedrons and microspheres composed of Mo2C particles. The results indicate that the nanofibers not only alleviate the aggregation and oxidation of internal carbides to achieve more active sites, but also provide a resistance-less path to facilitate the charge transfer process. Consequently, the resultant catalyst with unique one-dimensional (1D) structure exhibits enhanced HER performance under acidic conditions, affording an overpotential of 159 mV at a current density of 10 mA cm−2 and Tafel slope of 65.2 mV dec−1. This work may provide a new approach to develop Mo-based catalysts with excellent HER activity through morphological control.