Ni–Mo Nanocatalysts on N-Doped Graphite Nanotubes for Highly Efficient Electrochemical Hydrogen Evolution in Acid

Abstract

Developing noble-metal-free catalysts for electrochemical hydrogen evolution reactions (HER) with superior stability in acid is of critical importance for large-scale, low-cost hydrogen production from water electrolysis. Herein, we report a highly efficient and stable noble-metal-free HER catalyst, which is composed of Ni and MoC nanocrystals supported on N-doped graphite nanotubes. This catalyst shows very low overpotential (65 mV in 0.5 M HSO at a current density of 10 mA cm with a Tafel plot of 67 mV/dec) and good stability for HER in acidic electrolyte, which is a promising noble-metal-free HER catalyst.

W‐Doped MoO2/MoC Hybrids Encapsulated by P‐Doped Carbon Shells for Enhanced Electrocatalytic Hydrogen Evolution

“…It is shown that the performance of W‐MoO 2 /MoC@PC ( η 20 =209 mV) is superior to that of Mo 2 C/C‐lamellas ( η 20 =220 mV), Mo x C‐G hybrids ( η 4 =475 mV), Mo 2− x Fe x C ( η 5 =240 mV), commercial Mo 2 C particles ( η 20 =225 mV), Mo 2 C nanoparticles supported on XC‐72R carbon black ( η 8 =200 mV), Mo 2 C nanowires ( η 20 =220 mV) and Mo 2 C nanosheets ( η 20 =260 mV) synthesized via pyrolysis of their MoO x /pphenylenediamine hybrid precursors, MoWON/NGR ( η 20 =270 mV) and so on. The performance of W‐MoO 2 /MoC@PC is inferior to that of Co 6 Mo 6 C‐G ( η 20 =183 mV), Mo‐W 18 O 49 ( η 20 =75 mV), MoO 2 @PC‐RGO ( η 20 =90 mV), NiMo‐NGTs ( η 20 =79 mV), and so on. The comparison reveals that W‐MoO 2 /MoC@PC exhibits comparable HER catalytic activity in comparison with most other Mo‐based nanostructures.…”

Physically Adsorbed Metal Ions in Porous Supports as Electrocatalysts for Oxygen Evolution Reaction

“…As expected, Co 0.7 Fe 0.3 CB showed the small Tafel slope of 36.2 mV dec −1 (Figure 2c), which is lower than CoCB (58.7 mV dec −1 ), FeCB (39.5 mV dec −1 ), IrO 2 /CB (87.3 mV dec −1 ), and CB (183.1 mV dec −1 ). Moreover, the electrical impedance spectroscopies (EIS) of Co 0.7 Fe 0.3 CB, CoCB, and FeCB electrodes were further measured to understand the electrode reaction kinetics . As depicted in Figures 2d and S3 (Supporting Information), the Nyquist plot of Co 0.7 Fe 0.3 CB possesses an obviously smaller semicircle than that of CoCB and FeCB, suggesting the much faster electron transport of Co 0.7 Fe 0.3 CB.…”

Ni‐Assisted Low Temperature Synthesis of MoCx with Enhanced HER Activity

“…The diffraction peaks at 44.5°, 51.8° and 76.4° for Ni/C‐650 (without adding Mo source) in Figure b fit well with metallic Ni with fcc structure (PDF#04‐0850, labeled with •). Interestingly, the three particular peaks shifted by about 0.7° to the lower angle for MoC x /Ni‐650 in Figure b (labeled with ⧫) due to the Mo addition, which is believed to be the result of Ni−Mo alloying . In addition, the reflection at ca.…”

“…Encouragingly, Wang's group first synthesized molybdenum‐carbide‐modified N‐doped carbon vesicle encapsulating Ni nanoparticles (Mo x C−Ni@NCV) with outstanding catalytic HER performance . Li's group also reported a catalyst for HER, which was composed of Ni−Mo alloy and Mo 2 C nanoparticles supported on N‐doped graphite nanotubes (NiMo‐NGTs) . Very recently, Sun et al.…”