PPy enhanced Fe, W Co-doped Co₃O₄ free-standing electrode for highly-efficient oxygen evolution reaction

Abstract: Electrochemical catalysts for the oxygen evolution reaction (OER) play a key role in highly-efficient water splitting and many other important energy conversion applications. Transition metal oxides are promising OER catalysts. In this work, Fe, W co-doped Co₃O₄ was grown on carbon fiber cloth (FeWCo₃O₄/CFC) and polypyrrole (PPy)/carbon fiber cloth (FeWCo₃O₄/PPy/CFC) through a simple anodic electrodeposition method. The FeWCo₃O₄/CFC free-standing electrode reached an electrocatalytic current density of 30.7 mA cm⁻² at 400 mV overpotential with a Tafel slope of 177 mV dec⁻¹. The PPy can serve as conductive binder and improve the contact between FeWCo₃O₄ and substrate. The resulting FeWCo₃O₄/PPy/CFC free-standing electrode reached an electrocatalytic current density of 36.2 mA cm⁻² at 400 mV overpotential with a Tafel slope of 163 mV dec⁻¹. The FeWCo₃O₄/PPy/CFC free-standing electrode shows low electric resistance and is able to catalyze OER at 10 mA cm⁻² for 12 h without obvious decay under the optimized electrodeposition conditions. This study provides new insight for design and synthesis of highly-efficient OER catalyst. Graphical Abstract: [Figure not available: see fulltext.].