Iron regulates the interfacial charge distribution of transition metal phosphides for enhanced oxygen evolution reaction

Using earth abundant elements to develop oxygen evolution reaction (OER) electrocatalysts presents one of the most promising strategies to generate clean and renewable energy systems to deal with the ever-growing energy crisis. The challenge comes as how to rationally design the chemical composition and nanostructure to increase the OER efficiency. In this work, we demonstrated an operational ion strategy to improve OER performances of iron cobalt bimetallic phosphide (Fe0.5Co-P), which was fabricated by simultaneous annealing and phosphating metal organic framework (MOF) precursors. The iron regulates the charge density of the Co sites, changing the electronic structure of the phase interface for endowing dramatically enhanced OER activity. The Fe0.5Co-P catalyst possesses excellent durable and reliable characteristics and exhibits dramatically enhanced OER efficiency with an overpotential of only 260 mV to drive a current density of 10 mA cm-2 and a Tafel slope of 65.53 mV dec-1 in 1.0 M KOH. The work provides useful insights into the design and synthesis of multicomponent metal phosphides-based OER catalysts for practical application in water splitting.