In Situ Preparation of Mo2C Nanoparticles Embedded in Ketjenblack Carbon as Highly Efficient Electrocatalysts for Hydrogen Evolution

Recently, to enhance the catalytic activity of molybdenum carbide (Mo2C) electrocatalysts for the hydrogen evolution reaction (HER), the conductive carbon-based materials with different structures have been used to support Mo2C particles for providing sufficient catalytic hydrogen production sites. Nevertheless, it is always hard to use a simple method to ensure both uniform distribution of Mo2C particles and good charge transfer between Mo2C and carbon matrix. Herein, we used a low-cost carbonaceous material as ingredient via a facile method of in situ carbonization to design the structure of Mo2C nanoparticles embedded in chainlike Ketjenblack carbon (KB) with strong chemical link, to achieve the Mo2C/KB hybrid catalyst with uniform distribution of active Mo2C nanocrystals on KB for high density of catalytic sites and excellent charge transfer ability. Moreover, the effects of carbonization temperature and carbon content on the HER activity were investigated to optimize the Mo2C/KB catalyst. The optimized Mo2C/KB catalyst exhibits outstanding HER activity in both acidic and alkaline media with small Tafel slopes of 49 and 48 mV dec(-1), low overpotentials, and remarkable stability. The enhanced HER activity of Mo2C/KB catalyst could be ascribed to its unique chainlike structure with a large specific surface area of 580.3 m(2) g(-1), the high electronic conductivity, and active Mo2C nanocrystals protected by robust carbon matrix.