Influence of Low Magnetic Fields on Hydrogen Evolution Reaction Performance of NiCoP Electrocatalysts

Developing nonprecious, high-efficiency, and durable electrocatalysts for H₂ evolution in acidic media is highly desirable. Extensive research has focused on improving electrocatalyst activity through techniques like defect engineering, composite formation, and doping. Here, nickel-cobalt phosphide (NiCoP) nanorods' electrocatalytic activity enhancement by applying an external magnetic field is reported. The nanorods are synthesized via a simple hydrothermal method. When coated onto carbon paper, the NiCoP nanorods exhibit an overpotential of 100 mV at 10 mA cm^-2. However, under a low magnetic field of 2000 G, the overpotential reduced to 62 mV at 10 mA cm^-2 in 0.5 M H₂SO₄, demonstrating that the external magnetic field positively affects the kinetic process of the NiCoP nanostructure. The improved mass transport through the Lorentz force and the uniform alignment of magnetic moments of the material in the presence of a magnetic field serve for the purpose of enhanced hydrogen evolution reaction (HER) activity. The density functional theory-based calculations support this scenario that the spin alignment can boost HER activity. These results suggest an alternative strategy for further improving the HER properties of electrocatalysts by utilizing an external magnetic field.