A sulfur-doped Ni2P electrocatalyst for the hydrogen evolution reaction

Abstract

Hydrogen energy is considered to be one of the ideal clean energies to replace fossil fuels because of its high energy density, renewability and environmental friendliness. The design and development of efficient, stable and low-cost hydrogen evolution reaction (HER) electrocatalysts is the key to driving the industrialization of hydrogen production technology from electrochemical water splitting. In this work, sulfur-doped Ni₂P (S-Ni₂P) electrocatalysts with a porous structure were synthesized by simple one-step hydrothermal reaction. The composition, structure, morphology and HER properties of S-Ni₂P materials were regulated by adjusting the amount of sulfur doping. The results show that S-Ni₂P catalysts display a better HER catalytic performance than pure Ni₂P in acidic and alkaline electrolytes. Sulfur doping can significantly improve the catalytic activity of Ni₂P. With the increase of content of doped sulfur, the HER performance of S-Ni₂P materials is gradually improved. When the content of doped sulfur is 10%, the overpotentials of S_10%-Ni₂P in 0.5 M H₂SO₄ and 1 M KOH are 290 and 331 mV at 10 mA cm⁻² with the Tafel slope of 67.1 and 104.1 mV dec⁻¹, respectively, exhibiting the best HER catalytic activity among all S-Ni₂P materials. This is mainly due to the unique porous structure of S-Ni₂P, which can provide more catalytic active sites. At the same time, sulfur doping can adjust the electronic structure of Ni₂P so as to improve the intrinsic activity of the materials.