Cobalt‐Doping in Molybdenum‐Carbide Nanowires Toward Efficient Electrocatalytic Hydrogen Evolution

Abstract

Efficient hydrogen evolution reaction (HER) over noble‐metal‐free electrocatalysts provides one of the most promising pathways to face the energy crisis. Herein, facile cobalt‐doping based on Co‐modified MoOx–amine precursors is developed to optimize the electrochemical HER over Mo2C nanowires. The effective Co‐doping into Mo2C crystal structure increases the electron density around Fermi level, resulting in the reduced strength of Mo–H for facilitated HER kinetics. As expected, the Co‐Mo2C nanowires with an optimal Co/Mo ratio of 0.020 display a low overpotential (η10 = 140 and 118 mV for reaching a current density of –10 mA cm−2; η100 = 200 and 195 mV for reaching a current density of –100 mA cm−2), a small Tafel slope (39 and 44 mV dec−1), and a low onset overpotential (40 and 25 mV) in 0.5 m H2SO4 and 1.0 m KOH, respectively. This work highlights a feasible strategy to explore efficient electrocatalysts via engineering on composition and nanostructure.

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

“…Thus, we may declare that the N@Mo 2 C-3 nanosheet layer is composed of N-doped Mo 2 C nanocrystals and a porous N-doped carbon matrix. [65] The above results further corroborate that fine tuning the magnitude of the derivative organoimido ligands in POM precursors could assist the regulation of the number of intercalated N atoms in Mo 2 C electrocatalysts. [16][17][18][19][20][21] Also, the binding energy of Mo 6+ (Mo 3d 5/2 : 232.5 eV, 3d 3/2 : 235.5 eV) and Mo 4+ (Mo 3d 5/2 : 229.9 eV; 3d 3/2 : 233.0 eV) does not change much and is consistent with the literature values.…”

Stimulated Electrocatalytic Hydrogen Evolution Activity of MOF‐Derived MoS2 Basal Domains via Charge Injection through Surface Functionalization and Heteroatom Doping

“…Although heteroatom doping has been shown to trigger the electrocatalytic activity as explicitly shown in this work and recent studies, [33,[39][40][41] the same heteroatoms with different coordination configuration could result in distinctively different performance. As presented in the polarization curve in Figure S23 (Supporting Information), MoS-CoS-Zn-1pot exhibits inferior catalytic activity compared with MoS-CoS-Zn synthesized by MOF-route.…”

“…In the Mo 3d XPS spectrum (Figure 2d) of MoS, two peaks observed at 229.5 and 232.7 eV reflect Mo 3d 5/2 and Mo 3d 3/2 orbitals, respectively, indicating that Mo is in 4+ oxidation state. [33,34] Similarly, S 2p 3/2 (162.5 eV) and S 2p 1/2 (163. Nonetheless, in the MoS-CoS XPS spectrum, Mo 3d and S 2s binding energies are shifted compared with MoS, suggesting interactions between MoS 2 and CoS 2 in MoS-CoS hybrid.…”

Boosting the Electrocatalytic Activity of Co3O4 Nanosheets for a Li-O2 Battery through Modulating Inner Oxygen Vacancy and Exterior Co3+/Co2+ Ratio

“…[19][20][21] Our group and some other groups have reported the crystal plane dependence of the electrocatalytic activity of Co3O4 for Li-O2 battery. [12][13]22 Tuning the electronic structure to increase active sites through creating oxygen vacancies is another effective strategy to enhance the electrocatalytic activity of metal oxide catalysts for…”