A zeolite-type CoFe selenite via in-situ transformation of layered double hydroxide boosting the water oxidation performance in alkaline electrolyte

Abstract It is of significant importance and a great challenge to explore new electrocatalysts with highly activity and durability, above all, high mass activity and rapid kinetics, for oxygen evolution reaction (OER) due to the demand for clean energy. In this work, we prepared a three-dimensional (3D) CoFe-based zemannite-type selenite (KCFS) via in situ transformation of CoFe-layered double hydroxide (LDH) as both the precursor and template. The as-prepared CoFe-selenite affords low overpotential in 1.0 M KOH on glass carbon electrode (η@10 mA cm−2 = 274 mV) with Tafel slope of 45.6 mV dec−1, indicating rapid kinetics, in addition, keeps high current density around 10 mA/cm2 at least 50 h when applied voltage of 1.51 V. The excellent electrocatalytic performance of KCFS could be mainly attributed to its unique zeolite structure and compositions with bimetallic centres and SeO3 oxyanion, besides, it exhibits nanoellipsoid rough-surface morphology and hierarchical pores, which is beneficial to the enhanced exposure of the active sites, as well as the mass/charge transport and the electrolyte diffusion.