Enhanced hydrogen evolution reaction activity through samarium-doped nickel phosphide (Ni₂P) electrocatalyst

Hydrogen evolution reaction (HER) stands out among conventional hydrogen production processes by featuring excellent advantages. However, the uncompetitive production cost due to the low energy efficiency has hindered its development, necessitating the introduction of cost-effective electrocatalysts. In this study, we introduced samarium doping as a high-potential approach to improve the electrocatalytic properties of nickel phosphide (Ni₂P) for efficient HER. Samarium-doped Ni₂P was synthesized via a facile two-step vapor-solid reaction technique. Different physical and electrochemical analyses showed that samarium doping significantly improved pure Ni₂P characteristics, such as particle size, specific surface area, electrochemical hydrogen adsorption, intrinsic activity, electrochemical active surface area, and charge transfer ability in favor of HER. Namely, Ni₂P doped with 3%mol of samarium (Sm_0.03Ni₂P) with a Tafel slope of 67.8 mV/dec. and overpotential of 130.6 mV at a current density of 10 mA/cm² in 1.0 M KOH solution exhibited a notable performance, suggesting Sm_0.03Ni₂P and samarium doping as a remarkable electrocatalyst and promising promoter for efficient HER process, respectively.