Facile synthesis of ZnCo2O4 mesoporous structures with enhanced electrocatalytic oxygen evolution reaction properties†
Abstract
Recently, as one kind of ternary spinel metal oxide, ZnCo2O4 has attracted extensive attention in the energy storage and conversion field due to it being cost-effective, scalable, and environmentally friendly. Herein, porous ZnCo2O4 micro-spindles and truncated drums were synthesized by a solvent thermal route first and then with an annealing treatment with the precursors. The morphology and structure of ZnCo2O4 were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM). It is worth noting that ZnCo2O4 porous micro-spindles show a high surface area of 65.85 m2 g−1 with an average pore diameter of ∼6.34 nm. The as-prepared ZnCo2O4 materials, especially micro-spindles, exhibited good electrocatalytic water-splitting performance with excellent activity and stability. The ZnCo2O4 micro-spindle catalyst exhibits an overpotential of 0.389 V at the benchmark of a current density of 10 mA cm−2. The Tafel slope is 59.54 mV dec−1 and the OER overpotential of the catalyst shows no obvious increase during 7200 s. The high activity, low Tafel slope, and good stability will pave the way for the use of ZnCo2O4 micro-spindles in practical applications.