Hydrogen Evolution Reaction Property of Molybdenum Disulfide/Nickel Phosphide Hybrids in Alkaline Solution

Abstract

Abstract:The hydrogen evolution reaction (HER) property of molybdenum disulfide (MoS 2 ) is undesirable because of the insufficient active edge sites and the poor conductivity. To enhance HER performance of MoS 2 , nickel phosphide (Ni 2 P) was combined with this catalyst and three MoS 2 /Ni 2 P hybrids (38 wt % Ni 2 P addition for MoS 2 /Ni 2 P-38, 50 wt % Ni 2 P addition for MoS 2 /Ni 2 P-50, and 58 wt % Ni 2 P addition for MoS 2 /Ni 2 P-58) were fabricated via a hydrothermal synthesis process. Morphologies, crystallinities, chemical components, specific surface areas, and HER properties of the fabricated MoS 2 /Ni 2 P samples in an alkaline electrolyte were characterized and tested. In addition, the insight into the HER properties of as-prepared catalysts were revealed by the density functional theory (DFT) calculation. Additionally, the stabilities of pure MoS 2 , Ni 2 P, and MoS 2 /Ni 2 P-50 samples were evaluated. The results show that the addition of Ni 2 P can enhance the HER property of the MoS 2 catalyst. Although HER properties of the above-mentioned three MoS 2 /Ni 2 P hybrids are inferior to that of pure Ni 2 P, they are much higher than that of MoS 2 . Among as-prepared three hybrids, MoS 2 /Ni 2 P-50 exhibits the best HER performance, which may be due to its uniform morphology, large specific surface area, and excellent stability. The MoS 2 /Ni 2 P-50 hybrid shows a high cathodic current density (70 mA/cm 2 at −0.48 V), small Tafel slope (~58 mV/decade), and a low charge transfer resistance (0.83 kΩ·cm 2 ).

Oxide Electrocatalysts Based on Earth-Abundant Metals for Both Hydrogen- and Oxygen-Evolution Reactions

“…In acidic condition, materials such as sulfides, , carbides, nitrides, and metals have been used. Similarly, in the basic medium, catalysts such as sulfides, phosphides, carbides, and nitrides have been utilized. Very few oxides have shown HER activity in either acidic or alkaline environment.…”

“…For hydrogen-evolution reaction (HER), the high cost of platinum used in the Pt/C catalyst − and some of the Ir-based alternatives has led to the investigation of various other catalysts such as sulfides, phosphides, carbides, and nitrides . However, oxides, particularly perovskite oxides, with good HER activity in either acidic or basic condition are not very common.…”

Nickel sulfide and phosphide electrocatalysts for hydrogen evolution reaction: challenges and future perspectives

“…If the solvent is water, this method also is called hydrothermal synthesis. The synthesis of nickel suldes and phosphides via the solvothermal method has been conducted with water (hydrothermal method) [39][40][41][42][43][44][45][46][47] and other solvents such as ethanol, 48 oleylamine, 49 ethanolamine, 50 ethylene glycol, 51 triethylene glycol, 52 ethylenediamine 53 and mixed solvents. [54][55][56][57][58][59] The most used nickel precursor is nickel chloride, 39,41,42,47,54,56,57 while other precursors such as nickel nitrate, 39,59,60 nickel acetate 44,45,49,55,[61][62][63] and nickel foam 39,48,[50][51][52][53] have also been used.…”

“…[54][55][56][57][58][59] The most used nickel precursor is nickel chloride, 39,41,42,47,54,56,57 while other precursors such as nickel nitrate, 39,59,60 nickel acetate 44,45,49,55,[61][62][63] and nickel foam 39,48,[50][51][52][53] have also been used. Similar to the electrodeposition method, for the synthesis of nickel suldes, different sulfur precursors such as sulfur powder, 40,49,51,61 thiourea 39,40,62 and thioacetamide 35 have been used, but only NaH 2 PO 2 $H 2 O 41,42,56,57,59 and red phosphorus [43][44][45][46][47][48]50,[52][53][54][55]58,60 have been commonly used as the phosphorus precursor in the synthesis of nicke...…”

Sustainable Oxide Electrocatalyst for Hydrogen- and Oxygen-Evolution Reactions

“…For the hydrogen-evolution reaction (HER), the best electrocatalyst is Pt/C, which suffers from a similar problem as the precious metal catalysts for the OER, namely, high cost and lack of economic efficiency. Therefore, a range of materials have been studied for HER catalysis, such as phosphides, sulfides, − nitrides, carbides, and oxides . Despite the relative success of oxygen-deficient perovskites in OER catalysis, few members of this family have shown HER activity in alkaline conditions. , In addition, perovskite-type oxides based on nonprecious metals that show HER activity in acidic conditions are rare.…”