Template-free synthesis of three-dimensional NiFe-LDH hollow microsphere with enhanced OER performance in alkaline media

Flower-like hierarchical three-dimensional NiFe layered double hydroxides hollow microspheres (3D NiFe-LDH HMS), as one kind of novel non-noble metal electrocatalysts, have been fabricated in a template-free route for water oxidation. Both of the concentration of ammonium fluoride and the reaction time are adjusted to obtain a series of NiFe-LDH microspheres, with different internal structures from massive to hollow generated during the hydrothermal treatment, which improve the electrocatalytic activity of the NiFe-LDH catalysts towards the evolution reaction of oxygen. The optimized NiFe-LDH-0.4M HMS show the excellent OER performance in alkaline electrolyte with eta = 290 mV@10 mA cm(-2), and a Tafel slope of 51 mV dec(-1), which outperforms the benchmark RuO2 catalyst. The possible reason is attributed to the more exposure of active sites, and fast ion transport resulting from the hierarchical hollow structure. (C) 2018 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.