Direct Synthesis of Dual Mo-Based Functional Materials Derived from Molybdenite by Molten Salt Paired Electrolysis

A facile synthesis process that facilitates the industrial-scale production of catalysts is the prerequisite of the hydrogen evolution reaction (HER) industry. Molybdenum-based catalysts are ideal alternatives for precious-metal-based HER materials; however, they remain challenging in scale-up preparation due to the costly and complex Mo sources. Herein, we propose a molten salt paired electrolysis approach to synthesize transition-metal-doped Mo2C catalysts directly from molybdenite (mainly consisting of micrometer-scale MoS2 bulks), an earth-abundant natural Mo ore. Unlike Fe-doped Mo2C in which those transition metal dopants are inclined to diffuse into inner planes of Mo2C, this unique synthesis approach leverages the differences in transition metal diffusion energy barriers, ultimately leading to the development of Ni-doped Mo2C catalytic materials with specific Ni-enriched interfaces. Owing to the unique design and structures of the catalyst, the interfacially Ni-enriched Ni-doped Mo2C exhibited promising HER performance and long-term stability. Very interestingly, MoS2 nanoflakes, as side products, can be collected at the anode side while interfacially Ni-enriched Mo2C was concurrently obtained at the cathode side during the electrolytic synthesis process. This work not only deepens our knowledge on constructing active-site-enriched interfaces that are beneficial to HER but also gives clues to upcycling raw materials.