Engineering Hierarchical Porous Carbon-Supported Fe-Doped Cobalt Phosphides from MOF Templates for Alkaline Water Oxidation

Abstract

The development of high-performance, non-precious metal electrocatalysts for the oxygen evolution reaction (OER) is crucial for advancing sustainable hydrogen production through water splitting. Herein, we report a MOF-on-MOF strategy for synthesizing Fe-doped cobalt phosphide nanoparticles dispersed within a porous N-doped carbon matrix, designated as S-CoFeP. This can be achieved through the facile synthesis of a bimetallic ZnCo-MOF precursor, where Zn2+ acts as a morphology modulator. The subsequent pyrolysis process yields a sheet-like carbon framework, which facilitates the uniform growth of a CoFePBA. A final phosphorization step transforms this intermediate into the active S-CoFeP catalyst. Detailed characterization confirms the successful formation of Co2P as the primary phase, with Fe incorporated as a beneficial dopant. The optimized catalyst exhibits exceptional OER performance in alkaline media, achieving a small overpotential of 234 mV at 10 mA cm-2 and satisfactory durability for over 70 hours. It significantly outperforms both a monometallic cobalt phosphide counterpart and the benchmark RuO2. This work provides a good example for designing advanced OER electrocatalysts through synergistic morphology control and heteroatom doping, highlighting a promising path toward efficient and durable energy conversion systems.