Unveiling the Changes of Dinickel Phosphide (Ni2P) in Hydrogen Evolution Reaction: Toward a Deeper Mechanistic Understanding

Dinickel phosphide (Ni2P), an efficient electrocatalyst derived from commonly available elements, shows a noteworthy performance in the hydrogen evolution reaction (HER). This research includes an extensive analysis using diverse characterization techniques, including scanning electron microscopy, transmission electron microscopy, energy dispersive spectrometry, X-ray diffraction, X-ray absorption spectroscopy (XAS), electron paramagnetic resonance (EPR), and in situ Raman spectroscopy, revealing the structural change of Ni2P particles under a 100 or 400 mV overpotential during HER. Employing methods like Fourier transform infrared, in situ Raman spectroscopy, EPR, and XAS, the study uncovers structural and chemical changes. These include the emergence of nickel species, alterations in oxidation states, and the indication of Ni–O bond formation. Additionally, considerable morphological alterations in the particles are noted. These insights contribute to a deeper understanding of Ni2P's behavior and properties in HER conditions, shedding light on its catalytic efficiency and stability.