Bifunctional modulation of RuF modified CoP nanorod catalysts for efficient overall water splitting

Cobalt phosphide (CoP) is a promising non-noble metal electrocatalyst for overall water splitting, but its practical application is limited by intrinsically sluggish water dissociation kinetics and insufficient exposure of active sites. To address these challenges, this study proposes a Ru and F synergistic doping strategy to regulate the electronic structure of porous CoP by introducing lattice distortion. Density functional theory (DFT) calculations predict that such synergistic doping can establish an "adsorption-diffusion-dissociation" multi-element catalytic pathway during the reaction, where water molecules preferentially adsorb at Co sites and migrate to low-energy-barrier RuCo bridge sites for dissociation, with a water dissociation barrier as low as 0.23 eV. Based on this theoretical design, Ru-F-CoP was prepared in situ on a nickel foam substrate and systematically characterized. Structural analysis shows that Ru substitution for Co introduces positive chemical pressure and local lattice strain, leading to expansion of the unit cell parameters and reconstruction of the electronic environment. F doping further generates localized electric field effects, downshifts the Co d-band center, enhances Lewis acidity, and forms uniformly distributed mesoporous helical nanorod arrays, increasing the specific surface area from 93.9 m² g^-1 to 229.3 m² g^-1. Electrochemical testing results validate the design strategy, demonstrating excellent bifunctional catalytic performance in alkaline electrolyte, with HER and OER overpotentials of only 57 mV and 211 mV at 10 mA cm^-2, and an overall water-splitting voltage of just 1.521 V. This study provides new insights and theoretical guidance for the rational design of high-efficiency non-noble metal electrocatalysts.