Flower-like S-doped-Ni₂P mesoporous nanosheet-derived self-standing electrocatalytic electrode for boosting hydrogen evolution

Abstract

Developing cost-effective, highly active, and stable electrocatalysts for boosting electrochemical hydrogen evolution reaction (HER) in alkaline media is playing a critical role in meeting the demands of the hydrogen industry in the future. Herein, an efficient HER electrocatalyst based on flowerlike S-doped Ni 2 P mesoporous nanosheets (NSs) supported on nickel foam (S-Ni 2 P NSs/NF) was developed through an effective approach. The obtained S-Ni 2 P NSs/NF catalyst required low overpotential of only 87.5 and 179.1 mV to reach a current density of 10 and 50 mA cm −2 , respectively. Moreover, a small Tafel slope of 62.1 mV dec −1 for S-Ni 2 P NSs/NF demonstrated that the HER process occurred with very fast kinetics. Besides high HER activity, the synthesized S-Ni 2 P NSs/NF catalyst exhibited superior stability and long-term durability towards HER, which had the ability to operate for over 30 h without degradation in catalytic performance. The unique flower-like nanosheet structure with excellent mesoporous characteristics of S-Ni 2 P NSs/NF resulted in maximizing the electrochemical active surface area for providing a large number of electrocatalytic active sites. In addition, the S-doping effect could modulate the electronic structure of Ni species in Ni 2 P, leading to an acceleration of the adsorption rate of reaction intermediates on the surface of catalysts towards improving HER kinetics. The results not only demonstrate S-Ni 2 P NSs/NF as an active catalyst for HER, but offer an effective strategy for improving the catalytic activity of earth-abundant transition metal-based HER catalysts.

Unraveling the Structure and Surface Chemistry of the Phosphosulfide Phase Formed on Ni2P under Hydrodesulfurization Reaction Conditions: A DFT Study

“…In the (0001)-Ni 12 P 4 S 4 _3S surface, each Ni atom loses 0.09e, while in the (0001)-Ni 12 S 8 _3S surface, each Ni atom loses 0.17e compared to the (0001)-Ni 12 P 8 _3S surface. Because S has a higher electronegativity than P, the substitution of P for S leads to a higher charge transfer from Ni to S, 51 thereby oxidizing Ni and reducing S (Table S4). As Ni−S bonds provide a ligand effect stronger than that of the Ni−P bonds, 52 the electron-deficient Ni atoms would be expected to be highly active toward S adsorption due to an increase in their electrophilicity.…”

Nature-Inspired Design of Nano-Architecture-Aligned Ni5P4-Ni2P/NiS Arrays for Enhanced Electrocatalytic Activity of Hydrogen Evolution Reaction (HER)

“…However, it presents a new structure that has not been reported in the literature as shown in Tables and S2. Noticeably, all studies on the Ni–P–S ternary systems can be categorized into 4 groups based on the catalysts’ compositions, as follows: Producing intermediate nickel phosphosulfide compositions, like NiP x S 1– x , refs , and . Producing sulfur-doped nickel phosphide or phosphor-doped nickel sulfide, refs ,. Producing stoichiometric compounds, like NiPS 3 , NiS, and Ni 8 P 3 , and using further procedures such as ball-milling or electrochemical processes to exfoliate thin layers, refs , − ,. Generating the in situ epitaxial Ni 2 P nanodomains on 2D NiPS 3 nanosheets, ref . …”

Recent Advances in Multimetal and Doped Transition-Metal Phosphides for the Hydrogen Evolution Reaction at Different pH values

“…Sulfur is one of the most investigated nonmetal dopants. S doping has been successfully explored to improve the HER activity of TMPs, such as Ni 5 P 4 , Ni 2 P, CoP, Co 2 P, MoP, and NiCoP, in different pH media. For instance, Xing et al fabricated self-supported S-doped nickel phosphide nanoplate arrays on carbon paper (S-Ni 5 P 4 NPA/CP) containing different amounts of S .…”

“…15,120 Sulfur is one of the most investigated nonmetal dopants. S doping has been successfully explored to improve the HER activity of TMPs, such as Ni 5 P 4 , 15 Ni 2 P, 121 CoP, 122 Co 2 P, 123 MoP, 85 and NiCoP, 16 in different pH media. For instance, Xing et al fabricated self-supported S-doped nickel phosphide nanoplate arrays on carbon paper (S-Ni 5 P 4 NPA/CP) containing different amounts of S. 15 The amount of S had a significant effect on the HER performance of the S-Ni 5 P 4 NPA/CP samples (Figure 5a), with the highest activity reached for a sulfur content of 6%.…”