Unique heterointerface engineering of Ni₂P−MnP nanosheets coupled Co₂P nanoflowers as hierarchical dual-functional electrocatalyst for highly proficient overall water-splitting

A noble-metal-free electrocatalyst comprised of hybrid Ni₂P−MnP nanosheet coupled with Co₂P nanoflowers (Ni₂P−MnP@Co₂P) reinforced on nickel foam has been achieved with a unique heterostructure architecture for highly competent hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Tri-phased Ni₂P−MnP@Co₂P nanocrystal offers tremendously active and robust electrocatalytic efficacy heralded by low HER (60 mV) and OER (255 mV) to achieve (10 and 30) mA cm⁻² current densities, respectively. The outstanding electrochemical performance is due to the distinctive architectural feature, high surface area with optimum porosity, bountiful Ni₂P−MnP and Co₂P heterointerface interaction, and synergism among Ni₂P, MnP, and Co₂P multi-active sites. The Ni₂P−MnP@Co₂P (+,−) alkaline electrolyzer delivers a low cell voltage of 1.50 V at a current density of 10 mA cm⁻², along with astonishing long-term robustness. Moreover, the electrocatalyst displays a Faradaic yield of around (97.2 and 97.9) % at 50 mA cm⁻² for H₂ and O₂ respectively. This work is expected to pave the way for novel insights into the fabrication of efficient electrocatalysts for practical water-splitting applications.