Molybdenum oxide and molybdenum carbide coated carbon black as an electrocatalyst for hydrogen evolution reaction in acidic media

Molybdenum oxide and molybdenum carbide coated carbon black (MoO2-Mo2C/C) non noble metal hybrid electrocatalyst for hydrogen evolution reaction (HER) was synthesized from a mixture of metal molybdenum (Mo) powders and carbon black particles by a spark plasma coating (SPC) method. After the SPC process, the MoO2-Mo2C coating can anchor strongly on carbon black with the help of intermediate products Mo2C. The MoO2-Mo2C/C electrocatalyst exhibited a good HER performance with an onset overpotential of -121 mV, a high exchange current density of 6.8 x 10(-2) mA cm(-2) and a Tafel slope of -69 mV dec(-2) in 0.5 M H2SO4 solution. In addition, the MoO2-Mo2C/C showed much higher stability than Pt/C (20 wt% Pt supported on Vulcan XC-72 carbon black) after 3000 cycles of accelerated durability tests. The enhanced electrocatalytic activity and stability of MoO2-Mo2C/C electrocatalyst toward HER may originate from the Mo2C active sites formed in the process of SPC, and the effectively anchoring effect of MoO2-Mo2C coating on carbon black. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.