Heterostructured bimetallic phosphide nanowire arrays with lattice-torsion interfaces for efficient overall water splitting

Designing cost-effective and high-efficiency electrocatalysts is critical to the water splitting performance during hydrogen generation. Herein, we have developed Fe2P-Co2P heterostructure nanowire arrays with excellent lattice torsions and grain boundaries for highly efficient water splitting. According to the microstructural investigations and theoretical calculations, the lattice torsion interface not only contributes to the exposure of more active sites but also effectively tunes the adsorption energy of hydrogen/oxygen intermediates via the accumulation of charge redistribution. As a result, the Fe2P-Co2P heterostructure nanowire array exhibits exceptional bifunctional catalytic activity with overpotentials of 65 and 198 mV at 10 mA cm−2 for hydrogen and oxygen evolution reactions, respectively. Moreover, the Fe2P-Co2P/NF-assembled electrolyzer can deliver 10 mA cm−2 at an ultralow voltage of 1.51 V while resulting in a high solar-to-hydrogen conversion efficiency of 19.8% in the solar-driven water electrolysis cell.