Highly Active and Stable Hydrogen Evolution Electrocatalysts Based on Molybdenum Compounds on Carbon Nanotube–Graphene Hybrid Support

Abstract

Highly active and stable electrocatalysts for hydrogen evolution have been developed on the basis of molybdenum compounds (Mo2C, Mo2N, and MoS2) on carbon nanotube (CNT)-graphene hybrid support via a modified urea-glass route. By a simple modification of synthetic variables, the final phases are easily controlled from carbide, nitride to sulfide with homogeneous dispersion of nanocrystals on the CNT-graphene support. Among the prepared catalysts, Mo2C/CNT-graphene shows the highest activity for hydrogen evolution reaction with a small onset overpotential of 62 mV and Tafel slope of 58 mV/dec as well as an excellent stability in acid media. Such enhanced catalytic activity may originate from its low hydrogen binding energy and high conductivity. Moreover, the CNT-graphene hybrid support plays crucial roles to enhance the activity of molybdenum compounds by alleviating aggregation of the nanocrystals, providing a large area to contact with electrolyte, and facilitating the electron transfer.

Rationally Designed Hierarchically Structured Tungsten Nitride and Nitrogen‐Rich Graphene‐Like Carbon Nanocomposite as Efficient Hydrogen Evolution Electrocatalyst

“…As expected, the Pt/C electrode is highly active toward HER, demonstrating comparable activity to that as reported in literature 25, 28. As expected, the bulk‐phase WN electrode showed rather poor HER activity, as indicated by a large initial overpotential ( U onset ) of 331 mV and large overpotential of 492 mV at the representative current density of 10 mA cm −2 (η 10 ), respectively, which can be explained by its low number of active sites, poor electronic conductivity, and nonoptimized surface properties.…”

MoS2 Decorated Carbon Nanofibers as Efficient and Durable Electrocatalyst for Hydrogen Evolution Reaction

“…MoS2 grown over CNFs and MoS2-synthesized produced about 374 and 98 times higher current density at −0.30 V (vs. RHE) compared with the MoS2-commercial sample, respectively. Youn et al have reported an overpotential of 255 mV for MoS2 synthesized on carbon nanotube -graphene hybrid support at 10 mA/cm 2 [41].…”

“…Ren et al have synthesized monolayer of MoS2 quantum dots and observed a Tafel slope of 59 mV/decade [45]. MoS2 grown on Toray paper, MWCNT, and CNT/graphene showed a Tafel slope of 120, 109 and 100 mV/decade, respectively [41,46,47]. Some important parameters for MoS2 based HER catalysts are given in Table S1 for comparison.…”

Molybdenum Carbide Nanoparticles Coated into the Graphene Wrapping N‐Doped Porous Carbon Microspheres for Highly Efficient Electrocatalytic Hydrogen Evolution Both in Acidic and Alkaline Media

“…Although the Pt‐based materials have been proven to be the most efficient electrocatalysts for hydrogen evolution reaction (HER), the high cost, limited supply, and poor durability hinder their global‐scale application 3, 4. Therefore, much effort has been dedicated to develop robust nonnoble‐metal HER catalysts,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 such as cobalt‐, nickel‐, iron‐, tungsten‐, and molybdenum‐based materials.…”