Flower-shaped Fe–CoP@C composites derived from MOFs as an efficient electrocatalyst for oxygen evolution reaction

Abstract

Sluggish kinetics of oxygen evolution reaction (OER) dramatically hampers the large-scale application of electrochemical water splitting. It is of great importance to develop efficient and stable non-precious metal catalysts for OER. Using a hydrothermal-ion-exchange-high-temperature-phosphating approach, a novel 3D micron-flower-shaped composite (Fe–CoP@C) with strong coupling of iron-doped cobalt phosphide and carbon-based material was firstly prepared based on flower-like Co₃O₄@Co–MOF precursors. Fe–CoP nanoparticles loaded on functionalized carbon nanosheets can facilitate sufficient contact with the electrolyte and expose more catalytic active sites. The incorporation of Fe optimizes the electronic structure of the material and enables the material to exhibit excellent OER activity. In an alkaline electrolyte, Fe–CoP@C catalysts manifest superior electrocatalytic performance for OER with an overpotential of 259 mV at 10 mA cm⁻², a Tafel slope of 48.24 mV dec⁻¹. Benefiting from the strong coupling between nanoparticles and the carbon layer, the catalysts also exhibit faster reaction kinetics and higher structural stability. The composites display excellent long-term stability, with 108 h of continuous operation in alkaline solutions.