Enhancing Hydrogen Evolution Reaction Activities of 2H-Phase VS₂ Layers with Palladium Nanoparticles

Abstract

Effective hydrogen (H2) production with surface engineering of less active catalysts by an innovative approach is followed here. In this work, a non-noble 2H phase of VS2 layers, which showed poor activity for hydrogen evolution reaction (HER) in 0.5 M H2SO4, was made highly active by decorating palladium (Pd) nanoparticles (NPs) over VS2 layers. A density functional theory (DFT) study confirmed the successful binding of Pd with VS2, and the bond length in a Pd4 tetrahedron was measured to be 2.60 Å. In VS2–Pd, Pd as a Pd4 tetrahedron is pointed toward the VS2 layer, and the calculated Pd–S bond distance is 2.42 Å with some expansion of three Pd–Pd bonds (2.85 Å). From the density of states, it was confirmed that the band gap was too high for VS2 (0.2 eV; 2H phase) and was reduced to nearly zero in VS2–Pd (0.05 eV). In the electrocatalytic HER part, the obtained ΔG H values from DFT were 0.05, −0.45, and 0.22 eV for VS2/Pd4, Pd4, and VS2, respectively, which imply that VS2–Pd4 had improved HER activity compared to pristine VS2 and Pd4. A concentration-dependent study was carried out with molar ratios of Pd at 0.01, 0.05, and 0.1 M with VS2 layers. From the HER polarization study, VS2–Pd (0.05 M) showed an overpotential of 157 mV at 20 mA cm–2, which is 373 mV less than only VS2 with a Tafel slope of 75 mV dec–1 with overwhelming stability. These highly promising results will be interesting to make less active stable phases by incorporating metal NPs for efficient and stable H2 production.

Mo‐Doped Sulfur‐Vacancy‐Rich V1.11S2 Nanosheets for Efficient Hydrogen Evolution

“…In addition, long‐term stability at 10 mA cm −2 was also measured for the V 1.11 S 2 , 0.5Mo–V 1.11 S 2 , and 0.5Mo–V 1.11 S 2‐x electrocatalyst‐based electrode. As shown in Figures 3e and S8, during the 24 h operation, the potential of 0.5Mo–V 1.11 S 2‐x remained extremely stable at a current density of 10 mA cm −2 , better than V 1.11 S 2 , 0.5Mo–V 1.11 S 2 and many recently reported vanadium‐based HER electrocatalysts [58–59,64] . For comparison, the potential of 20 wt.% Pt/C drops dramatically with the extension of test time, which is consistent with previous studies [65–66] .…”

“…As shown in Figures 3e and S8, during the 24 h operation, the potential of 0.5Mo-V 1.11 S 2-x remained extremely stable at a current density of 10 mA cm À 2 , better than V 1.11 S 2 , 0.5Mo-V 1.11 S 2 and many recently reported vanadium-based HER electrocatalysts. [58][59]64] For comparison, the potential of 20 wt.% Pt/C drops dramatically with the extension of test time, which is consistent with previous studies. [65][66] Moreover, the polarization curve of À 2 , (e) the stable operation of the 0.5Mo-V 1.11 S 2-x electrode running at the current density of 10 mA cm À 2 , and 100 mA cm À 2 in 0.5 mol L À 1 H 2 SO 4 for a total duration of 24 h. ChemistrySelect 0.5Mo-V 1.11 S 2-x after 24 h operation remains nearly unchangeable (Figure S9).…”

Rational Design and Controlled Synthesis of V‐Doped Ni3S2/NixPy Heterostructured Nanosheets for the Hydrogen Evolution Reaction

“…[8][9][10][11] However,t heir large-scale industrial applicationsh ave been limited due to high cost and poor stability. [12,13] Therefore, cost-effective and highly efficient tran-sition metal compounds such as transition metal oxides, [14,15] carbides/nitrides, [16][17][18] sulfides, [19][20][21] and phosphides [22][23][24][25] have attracted ag reat deal of attention for HER.…”

Accelerated discovery of superoxide-dismutase nanozymes via high-throughput computational screening

“…These results have demonstrated that the screening principles can be easily implemented in computer programs for the high-throughput screening of NMs with intrinsic SOD-like activity. Among these materials, T-phase transition metal dichalcogenides (T-TMDCs, PtS 2 45 , ZrS 2 46 , ZrSe 2 46 , SnS 2 47 , HfS 2 48 ) and H-TMDCs (MoTe 2 49 , WSe 2 50 , WTe 2 51 , VS 2 52 ) have been experimentally reported. They existed in the form of single layers supported on substrates or a few layers in solutions 53 – 57 .…”