Modulation of interfacial electronic structure in Ni3P/NiFe LDH p–n junction for efficient oxygen evolution at ampere-level current density

Abstract

The development of efficient non-noble metal catalysts that can operate at high current densities for sluggish oxygen evolution is crucial for the large-scale commercialization of water electrolysis. Herein, we have developed a heterostructure oxygen evolution anode material that satisfies the requirements of ampere-level current density using a straightforward calcination-electroplating approach. Due to the natural p–n junction interface, a built-in electric field is induced in the Ni₃P/NiFe LDH electrode, resulting in high conductivity and low gas transmission resistance. As a result of its heterogeneous structure, abundant active sites, and rapid interfacial electron transfer, this Ni₃P/NiFe LDH exhibits outstanding catalytic performance, achieving an oxygen evolution current density of 1.4 A cm⁻² with an ultra-low overpotential of 304 mV. DFT calculations indicate that the formed p–n junction effectively drives electron transfer and directly influences the charge density surrounding the active center, thereby enhancing intrinsic activity. This study highlights the potential use of non-noble metal-based heterojunction materials as efficient catalysts for the oxygen evolution in alkaline water electrolysis.