Tensile-strain-driven interstitial Ru doping structure on an FeCoP/FF electrode accelerates the reaction kinetics of water electrolysis

Abstract

Ru atoms with a large radius are often doped into a lattice as substituents due to reaction kinetics and thermodynamics limitations. Therefore, overcoming kinetic resistance to realize interstitial Ru doping in phosphides and establishing the internal relationship of its electrocatalytic performance are challenging. Considering that the tensile strain induced by a quenching-induced huge temperature difference can provide the possibility of interstitial doping, an interstitially Ru-doped FeCoP/FF electrode with 2.32% tensile strain was innovatively constructed by a strain-driven interstitial Ru doping strategy. As expected, the Ru-FeCoP/FF∥Ru-FeCoP/FF electrolyzer needs a cell voltage of only 1.64 V to deliver 1 A cm⁻². Notably, the tensile strain and interstitially doped Ru synergistically promote the movement of electrons from Fe and Co sites to P and plummeting of the activation energy (E_a), thus accelerating the reaction kinetics of HER and OER. Overall, this work provides new ideas for designing an Ru interstitially doped electrode and optimizing the HER and OER kinetics.