Ultrafine Molybdenum Carbide Nanoparticles Composited with Carbon as a Highly Active Hydrogen‐Evolution Electrocatalyst

Abstract

The replacement of platinum with non-precious-metal electrocatalysts with high efficiency and superior stability for the hydrogen-evolution reaction (HER) remains a great challenge. Herein, we report the one-step synthesis of uniform, ultrafine molybdenum carbide (Mo2C) nanoparticles (NPs) within a carbon matrix from inexpensive starting materials (dicyanamide and ammonium molybdate). The optimized catalyst consisting of Mo2C NPs with sizes lower than 3 nm encapsulated by ultrathin graphene shells (ca. 1-3 layers) showed superior HER activity in acidic media, with a very low onset potential of -6 mV, a small Tafel slope of 41 mV dec(-1), and a large exchange current density of 0.179 mA cm(-2), as well as good stability during operation for 12 h. These excellent properties are similar to those of state-of-the-art 20% Pt/C and make the catalyst one of the most active acid-stable electrocatalysts ever reported for HER.

Ruthenium-cobalt nanoalloys encapsulated in nitrogen-doped graphene as active electrocatalysts for producing hydrogen in alkaline media

“…Besides, the electrochemical impedance spectroscopy images (Supplementary Fig. 15) showed that the Co@NC has a biggest semicircle radius, indicative of a slightly higher charge-transfer impedance than of S-1 (8.53 Ω), of S-2 (8.55 Ω), of S-3 (8.58 Ω), of S-4, of S-5 (8.53 Ω) and of S-6 (8.47 Ω) (refs 51, 52). Therefore, alloying Co with small amount of Ru could lead to a higher charge-transfer rate and more facile catalytic kinetics toward HER.…”

Fine Tuning Electronic Structure of Catalysts through Atomic Engineering for Enhanced Hydrogen Evolution

“…[36] However, further, it was demonstrated that the intrinsic HER activity of Mo 2 C is usually limited by their large density of empty d-orbitals on the Mo, which restricts the desorption of adsorbed H (H ads ) to generate H 2 . [43] However, nitrogen-doping (N-doping) often intermixes into carbon matrix rather than intercalating into Mo 2 C active sites, [16,[44][45][46][47][48] and thus how to construct a controllable N-doping into Mo 2 C activation site still remains a great challenge. [43] However, nitrogen-doping (N-doping) often intermixes into carbon matrix rather than intercalating into Mo 2 C active sites, [16,[44][45][46][47][48] and thus how to construct a controllable N-doping into Mo 2 C activation site still remains a great challenge.…”

Synthesis and characterization of an IrO2–Fe2O3 electrocatalyst for the hydrogen evolution reaction in acidic water electrolysis

“…[1][2][3][4] To date, extensive effort has been devoted to exploring advanced techniques for hydrogen production. [5][6][7][8][9][10] Water electrolysis is the simplest electrochemical procedure for producing pure hydrogen and has been one of the most promising processes for a hydrogen-based economy.…”