Phase Electronic Structure Tuning via Pt, P-Doped Ni₄Mo-Implanted Ti₄O₇ for Highly Efficient Water Splitting and Mg/Seawater Batteries

Fine-tuning nanoscale structures, morphologies, and electronic states are crucial for creating efficient water-splitting electrocatalysts. In this study, a method for electronic structure engineering to enhance overall water splitting in a corrosion-resistant electrocatalyst matrix by integrating Pt, P dual-doped Ni₄Mo electrocatalysts onto a Ti₄O₇ nanorod grown on carbon cloth (Pt, P-Ni₄Mo-Ti₄O₇/CC) is introduced. By optimizing platinum and phosphorus concentrations to 1.18% and 2.42%, respectively, low overpotentials are achieved remarkably: 24 mV at 10 mA cm^-2 for the hydrogen evolution reaction and 290 mV at 20 mA cm^-2 for the oxygen evolution reaction in 1.0 m KOH. These values approach or surpass those of benchmark Pt-C and IrO₂ catalysts. Additionally, the Pt, P-Ni₄Mo-Ti₄O₇/CC bifunctional electrocatalyst displays low cell potentials across various mediums, maintaining excellent current retention (96% stability after 40 h in mimic seawater at 20 mA cm^-2) and demonstrating strong corrosion resistance and suitability for seawater electrolysis. As a cathode in magnesium/seawater batteries, it achieves a power density of 7.2 mW cm^-2 and maintains stability for 100 h. Density functional theory simulations confirm that P, Pt doping-assisted electronic structure modifications augment electrical conductivity and active sites in the hybrid electrocatalysts.