Constructing Ru-P/O-transition metal bridge enabling high-performance oxygen evolution reaction

Abstract

Incorporating low-concentration precious metals into transition metal phosphides (TMPs) may represent a promising strategy to achieve improved catalytic performance of oxygen evolution reaction (OER). We design RuP₄ clusters immobilized on porous NiFeP nanosheets with Ru-P/O-TM bridge (RuP-NiFeP) for effective OER. The Ru-P/O-Ni/Fe bridges formed between the RuP₄ clusters and the NiFeP facilitate electron transfer between oxyphilic Ru atoms and Ni/Fe atoms, enabling Ru to achieve optimized reactant/intermediate adsorption. Advanced characterizations and theoretical calculations reveal that the incorporation of Ru species leads to the upshift of d band center and the formation of more disordered γ-NiOOH. The Ru-based clusters and the achieved disordered γ-NiOOH may deliver synergistic effect to further enhance the OER capability of RuP-NiFeP. Moreover, the presence of Ru species shifts the OER mechanism from the absorbate evolution mechanism (AEM) pathway (NiFeP) to the lattice oxygen mechanism (LOM) pathway, with *OH deprotonation (*OH → *O) as the rate-determining step (RDS). The RuP-NiFeP catalyst exhibits remarkable alkaline OER activity, requiring only an overpotential of 225 mV to achieve a current density of 100 mA cm⁻², and retains its performance with a minimal current density decay of 1.9% after stability test. This work offers valuable insights into the design of cost-effective and highly efficient electrocatalysts for alkaline OER.