Mesoporous NiO with different morphology: Synthesis, characterization and their evaluation for oxygen evolution reaction

Mesoporous NiO samples with different morphology were synthesized by hydrothermal method, and they were studied as electrocatalysts for oxygen evolution reaction in alkaline solution. The NiO samples were characterized by X-ray diffraction, transmission electron microscopy, N-2-adsorption, scanning electron microscopy and X-ray photoelectron spectroscopy. The critical synthesis parameters like hydrothermal reaction temperature, time and molar ratio of precursors were varied using Taguchi experimental method to investigate their effect on morphology and specific surface area of mesoporous NiO samples. The characterization data illustrated the formation of nanoplates, nanorods, and nanoparticles. All the NiO samples exhibited mesoporosity and the specific surface area values in the range of 88-156 m(2)/g. One of the synthesized mesoporous NiO samples, largely constituting of nanoplates and nanorods with high porosity, exhibited a Tafel slope of 62 mV/dec and achieved a current density of 41.6 mA/cm(2) at 1.6 V (vs. RHE). It showed better electrocatalytic activity for oxygen evolution reaction than remaining samples. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved