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

Abstract

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 m2 g–1, the high electronic conductivity, and active Mo2C nanocrystals protected by robust carbon matrix.

Synthesis of Mo2C and W2C Nanoparticle Electrocatalysts for the Efficient Hydrogen Evolution Reaction in Alkali and Acid Electrolytes

“…In addition, the G band was positioned at 1,582 cm −1 and the D band was positioned at 1,349 cm −1 , which corresponds to the sp 2− bonded carbon atoms and disarranged graphite carbon, respectively (Ma F. et al, 2015). The intensity ratio of the D-band to the G-band (i.e., I D /I G ) is 0.85 for Mo 2 C, comparable to long-time carbonized graphene layers with high conductivity, which may facilitate charge transfer during HER (Li et al, 2016; Lv et al, 2017; Wang et al, 2017). For commercial and chemically reduced W 2 C, the strong peaks observed at 693 and 807 cm −1 originate from the stretching vibration of W-C (Yan et al, 2017).…”

Effect of the Solvent Ratio (Ethylene Glycol/Water) on the Preparation of an Iron Sulfide Electrocatalyst and Its Activity towards Overall Water Splitting

“…where, C dl is the area‐normalized double layer capacitance. The area‐normalized double layer capacitance of an atomically smooth surface in 1.0 M KOH ranges between 0.02–0.06 mF cm −2 and therefore, the value was taken as 0.04 mF cm −2 . Cyclic voltammetry (CV) was performed at different scan rates (ν) between a narrow non‐Faradaic region.…”

“…The area-normalized double layer capacitance of an atomically smooth surface in 1.0 M KOH ranges between 0.02-0.06 mF cm À 2 and therefore, the value was taken as 0.04 mF cm À 2 . [49][50] Cyclic voltammetry (CV) was performed at different scan rates (ν) between a narrow non-Faradaic region. ΔJ value at 1.16 V (vs RHE) was calculated taking the following equation:…”

Understanding the synergetic interaction within α-MoC/β-Mo2C heterostructured electrocatalyst

“…1 These authors contributed equally to this work. sively explored for HER [8][9][10][11][12][13] . Furthermore, the structural design of electrocatalysts is indispensable for activity enhancement.…”