3D Nanostructured Nickel Hydroxide as an Efficient Electrocatalyst for Oxygen Evolution Reaction

The exploration of high-efficiency and reliable non-precious metal electrocatalysts for overall water splitting is greatly vital and challenging for scientists to explore the physical structure effects with OER catalysts. Herein, we firstly developed three-dimensional ɑlpha-nickel hydroxide as an advantageous electrocatalyst for OER by a simple solvothermal method. By controlling the solvent, two kinds of regular and one kind of irregular pure ɑlpha-nickel hydroxide were successfully synthesized. Two regular catalysts’ catalytic activity can be enhanced by the level of regularity increasing. Interestingly, with the increase of irregularity, compared with nanosphere-like Ni(OH)2, nanoparticle-sphere-like Ni(OH)2 sample’s specific surface areas, the number of ion transport channels, and reaction kinetics performance also raise, which actually enhances catalytic activity. In a word, the most irregular Ni(OH)2-NPS has the best electrocatalytic activity (η = 250 mV) and the lowest Tafel slope (73.9 mV dec−1), and the outstanding constancy (8 h) at 1.48 V (vs. RHE) could be achieved, meanwhile, the benchmark RuO2 (340 mV and 87.4 mV dec−1) is also inferior to Ni(OH)2-NPS. By comparing three Ni(OH)2 samples, this work provides a new single transition metal system for about 3D materials and facilitates the development of highly efficient water oxidation catalysts.Graphical Abstract