Facile synthesis of vanadium-modulated CoFeP@C nanoparticles to enhance intrinsic activity and stability for high-performance oxygen evolution reaction

Abstract

Electrocatalytic water decomposition is a sustainable method for producing hydrogen, but its application is hindered by the slow kinetics of the anodic reaction. The development of cost-effective electrocatalysts is key to realizing efficient water splitting for hydrogen production. In this study, a technique was proposed for synthesizing vanadium-modulated carbon-coated CoFeP nanoparticles (V-CoFeP@C) using cobalt-iron prussian blue analogues (CoFe PBAs) as templates. The experimental results demonstrated that the unique heterostructure of V-CoFeP@C provided abundant active sites and a large specific surface area (33.047 m² g⁻¹). In a 1.0 M KOH solution, the OER overpotential was 265 mV and the Tafel slope was 57.15 mV dec⁻¹ at a current density of 10 mA cm⁻². The introduction of V, endowed with unique intrinsic properties (multivalent states, matched ionic radius, and high Lewis acidity), modulated the electronic structure, increased the density of active sites, and transformed Co and Fe ions to higher oxidation states. This not only enhanced the catalytic performance but also enabled the catalyst to exhibit excellent OER activity. Additionally, V-CoFeP@C showed good stability, maintaining long-term operation at a current density of 10 mA cm⁻². This work provides a valuable reference for enhancing the stability of heterojunction electrocatalysts and optimizing trimetal nanostructures.