Synergistically Tuning Water and Hydrogen Binding Abilities Over Co₄N by Cr Doping for Exceptional Alkaline Hydrogen Evolution Electrocatalysis

Abstract

Searching for highly efficient and cost‐effective electrocatalysts toward the hydrogen evolution reaction (HER) in alkaline electrolyte is highly desirable for the development of alkaline water splitting, but still remains a significant challenge. Herein, the rational design of Cr‐doped Co4N nanorod arrays grown on carbon cloth (Cr–Co4N/CC) that can efficiently catalyze the HER in alkaline media is reported. It displays outstanding performance, with the exceptionally small overpotential of 21 mV to obtain the current density of 10 mA cm−2 and good stability in 1.0 m KOH, which is even better than the commercial Pt/C electrocatalyst, and much lower than most of the reported transition metal nitride‐based and other non‐noble metal‐based electrocatalysts toward the alkaline HER. Density functional theory (DFT) calculations and experimental results reveal that the Cr atoms not only act as oxophilic sites for boosting water adsorption and dissociation, but also modulate the electronic structure of Co4N to endow optimized hydrogen binding abilities on Co atoms, thereby leading to accelerating both the alkaline Volmer and Heyrovsky reaction kinetics. In addition, this strategy can be extended to other metals (such as Mo, Mn, and Fe) doped Co4N electrocatalysts, thus may open up a new avenue for the rational design of highly efficient transition metal nitride‐based HER catalysts and beyond.

Highly dispersed ultrafine Ni particles embedded into MOF-74 arrays by partial carbonization for highly efficient hydrogen evolution

“…4a shows the HER catalytic activities of various Ni NPs/C@Ni-MOF-74/NF with different carbonization times (6-24 h), and their overpotentials at 10 mA cm À2 are arranged in the following order: Ni@Ni-MOF-74/NF(18 h) is near the theoretical Tafel value (116 mV dec À1 ) associated with the Volmer rate-determining step, indicating that the Ni NPs/C@Ni-MOF-74/NF(18 h) undergoes the Volmer-Heyrovsky mechanism for HER in alkaline media. 49 The Tafel slopes of these catalysts after partial carbonization are lower than that of Ni-MOF-74/NF, and this reveals a more efficient charge transfer between the catalyst and electrolyte during the HER process. Accordingly, the partial carbonization method represents a powerful strategy to enhance the HER electrocatalytic activity of MOF-based catalysts.…”

Electrocatalytic Hydrogen Evolution of Ultrathin Co‐Mo5N6 Heterojunction with Interfacial Electron Redistribution

“…d) C dl values of Co‐Mo 5 N 6 , Mo 5 N 6 , and MoN in 1.0 m KOH. e) Comparison of the overpotential at 10 mA cm −2 among different transition metals nitrides: Ni 3 N/Ni, [ 21 ] Cr Doping Co 4 N, [ 22 ] NiMoN@NiFeN, [ 7a ] NiMoN, [ 3d ] Ta 5 N 6 , [ 23 ] Mo 5 N 6 , [ 6a ] W 2 N 3 , [ 10a ] NiCoN, [ 24 ] MoC/MoN, [ 25 ] and Co‐Ni 3 N [ 17 ] (from right to left). f) Comparison HER polarization curves of Co‐Mo 5 N 6 sample after 30 000 cyclic voltammetry (CV) and Chronoamperometric (it) tests.…”

Synergistically Tuning Electronic Structure of Porous β‐Mo2C Spheres by Co Doping and Mo‐Vacancies Defect Engineering for Optimizing Hydrogen Evolution Reaction Activity

“…Electrochemical hydrogen evolution reaction (HER) has been attracted more and more attention recently since it is considered as one of the greenest technologies to produce hydrogen. [ 10–13 ] At present, Pt‐based materials are still the most outstanding noble‐metal‐based HER catalysts. [ 14,15 ] However, they cannot be accepted by the market due to the insufficient Pt reserves and high expense.…”