Hexagonal β-Ni(OH)2 nanoplates with oxygen vacancies as efficient catalysts for the oxygen evolution reaction

초록

Water splitting system by transition metal-based catalysts has drawn much attention in renewable energy storage and conversion system. In this study, beta-Ni(OH)(2) nanoplates with abundant oxygen vacancies were synthesized via the hydrothermal method followed by a partial reduction reaction in a mild hydrogen atmosphere, and applied to the oxygen evolution reaction (OER) in an alkaline solution. The beta-Ni(OH)(2) nanoplates prepared by partial reduction in a hydrogen atmosphere at 100 degrees C exhibited a current density of 10 mA cm(-2) at a low overpotential of 340 mV in 1 M KOH; the overpotential was much lower than those required for pristine beta-Ni(OH)(2) nanoplates (391 mV) and air-treated beta-Ni(OH)(2) nanoplates (369 mV). Furthermore, the H-2-treated beta-Ni(OH)(2) nanoplates also displayed outstanding long-term stability even after 1000 cyclic voltammetry cycles. This excellent OER activity and stability could be ascribed to the abundant oxygen vacancies and a well-defined hexagonal structure. It is worth noting that this method will offer a facile synthesis of metal hydroxides for generating oxygen vacancy, improving the electrochemical performance of energy storage applications. (C) 2019 Elsevier Ltd. All rights reserved.

키워드