Construction of a ternary NiFeCrP_X heterojunction catalyst via synergistic doping and phosphorization engineering for enhanced overall water splitting

To address the poor conductivity and insufficient HER activity of NiFe-LDH, this study proposes a synergistic strategy integrating transition metal doping and phosphorization engineering. This approach enables in-situ fabrication of a self-supporting NiFeCrP_X/NF heterojunction catalyst. Cr³⁺ incorporation optimizes the Ni/Fe active centers and facilitates formation of a NiFeCr-LTH precursor, which converts into a multiphase Ni₂P–FeP₂–Cr₁₂P₇ heterojunction during phosphorization. This heterostructure elevates bulk conductivity and accelerates interfacial charge-transfer kinetics. Consequently, NiFeCrP_X/NF exhibits outstanding bifunctional performance, achieving 100 mA cm⁻² at low overpotentials of 210 mV for HER and 247 mV for OER in alkaline electrolyte. Moreover, it drives overall water splitting at 10 mA cm⁻² with only 1.57 V and sustains stable operation for over 100 h. This study provides a design strategy for efficient dual-function electrocatalysts via synergistic transition metal doping and heterojunction engineering.