Plasma Engineering of Basal Sulfur Sites on MoS₂@Ni₃S₂ Nanorods for the Alkaline Hydrogen Evolution Reaction

Abstract

Inexpensive and efficient catalysts are crucial to industrial adoption of the electrochemical hydrogen evolution reaction (HER) to produce hydrogen. Although two‐dimensional (2D) MoS2 materials have large specific surface areas, the catalytic efficiency is normally low. In this work, Ag and other dopants are plasma‐implanted into MoS2 to tailor the surface and interface to enhance the HER activity. The HER activty increases initially and then decreases with increasing dopant concentrations and implantation of Ag is observed to produce better results than Ti, Zr, Cr, N, and C. At a current density of 400 mA cm−2, the overpotential of Ag500‐MoS2@Ni3S2/NF is 150 mV and the Tafel slope is 41.7 mV dec−1. First‐principles calculation and experimental results reveal that Ag has higher hydrogen adsorption activity than the other dopants and the recovered S sites on the basal plane caused by plasma doping facilitate water splitting. In the two‐electrode overall water splitting system with Ag500‐MoS2@Ni3S2/NF, a small cell voltage of 1.47 V yields 10 mA cm−2 and very little degradation is observed after operation for 70 hours. The results reveal a flexible and controllable strategy to optimize the surface and interface of MoS2 boding well for hydrogen production by commercial water splitting.

Underfocus Laser Induced Ni Nanoparticles Embedded Metallic MoN Microrods as Patterned Electrode for Efficient Overall Water Splitting

“…Recently, non‐noble metal‐based catalysts had been identified as the alternative of noble metal‐based one to settle down water splitting, such as transition metal alloys, [ 6 ] nitrides, [ 7 ] sulfides, [ 8 ] carbides, [ 9 ] and phosphides. [ 10 ] Especially, molybdenum nitride possessed metallic conductivity and excellent mechanical robustness by virtue of their unique structure, where nitrogen atoms occupied interstitial positions in the metal lattice.…”

Rational Synthesis of Core‐Shell‐Structured Nickel Sulfide‐Based Nanostructures for Efficient Seawater Electrolysis

“…The former is assigned to the S-metal bonds, and the latter signals are ascribed to the surface SO bonds due to the significant interface interaction between Ni 3 S 2 and FeNi LDH. [32] The signal corresponded to S-metal bonds in S 2p spectrum of NiS@LDH/NF shifts to lower binding energy, verifying the existence of NiSFe (Ni) bridging units and the interface electron transfer from Ni 3 S 2 to FeNi LDH. [33] And the O 1s spectrum for LDH/NF in Figure 2f shows two distinct peaks at 530.2 and 531.5 eV, which are assigned to Ni/FeO species and surface-adsorbed oxygen species.…”

Heterojunction of Metal Plasmas and CoO Nanofilms for Ultraefficient Activity to Oxygen Evolution Electrocatalysts

“…The O 1s binding energy peaks in these electrodes are shifted to the lower energy direction compared with pure CoO (Figures f and S15). Therefore, the Ti, Cr, Ag, and Zr outer layer loses electrons, while the O outer orbital gains electrons, and electrons are transferred from Ti, Cr, Ag, and Zr to the O outer layer . The electrons of the metal layer are transferred into CoO, making the metal region positively charged, which further promotes the adsorption of OH – .…”

“…cleverly prepared Co-doped Ni 3 S 2 nanocones by vulcanizing a cobalt oxide nanofilm on the porous nickel foam (NF); the electrode exhibits excellent catalytic reactions, reaching an overpotential of 297 mV at a current density of 20 mA cm –2 . It mainly covers oxides, sulfides, hydroxides, nitrides, and carbides of these transition metals. − Because of its unique chemical properties, variable valences, and abundant sulfur active sites, it has already demonstrated certain electrocatalytic activity in OER . However, there is still room for further improvement in its oxygen evolution catalytic performance …”