Nanoflower like FeNi–B–P based on bifunctional nickel foam as a binder free electrocatalyst for high-efficiency oxygen evolution reaction

Abstract

Nickel foam as a current collector and substrate material is frequently utilized in electrochemical applications such as supercapacitors, batteries and the promising oxygen evolution reaction (OER). Herein, nanoflower like FeNi–B–P self-growing on nickel foam (FNBP/NF) is developed by electrodeposition and the B/P molar ratios within FNBP/NF are regulated to investigate the best OER performance at different ratios of boron and phosphorus. Moreover, the NF in this study achieves dual functionalization. It serves not only as a self-supporting formwork to maintain the intrinsic conductivity of the composite, but also as nickel source to provide attachment points and a growing environment. Thanks to the strong skeleton of NF, the catalyst shows extreme stability, as it remains almost constant during a 24 h chronopotentiometry test. Meanwhile, the convective effect of the NF prevents the accumulation of gas products at the interface, accelerating the precipitation of O2 and reducing contact resistance. Through electrochemical treatment, high-valence iron and nickel ions exhibit a synergistic effect that accelerates the coupling of O–O bonds, thereby promoting the evolution of O2. In 1.0 M KOH solution, the OER performance of FNBP/NF has been explored, when the current densities are 10 and 50 mA cm−2, the corresponding overpotentials are 253 and 318 mV, respectively, suggesting satisfactory electrocatalytic activity. Field emission scanning electron microscopy reveals a unique nanoflower-like morphology of FNBP/NF, providing abundant accessible sites for effective contact between the active substance and reactants. This study introduces bifunctional NF in OER catalysis to achieve dual synergistic effects, both synergistic effects of high-valence Fe–Ni ions and convective effect of NF, which accelerate O2 releasing and effectively reduce contact resistance, presenting a novel approach to achieving high-efficiency oxygen evolution.