High OER performance Ni(OH)2 with hierarchical structure

A stable, efficient, and low-cost oxygen evolution reaction catalyst is very momentous to deal with energy crisis and achieve sustainable energy conversion and storage. Herein, the composite of Ni(OH)(2) and reduced graphene oxide were obtained by a hydrothermal method at a high temperature and high pressure in a one-step hydrothermal process. SEM images showed that a multilayer sandwich structure with reduced graphene oxide in the middle of two layers of Ni(OH)(2) was achieved for the electrode. This unique hierarchical catalyst exhibited remarkable oxygen evolution reaction (OER) electrochemical activity in 1 M KOH media: a 313-mV overpotential at 10 mA cm(-2), a small Tafel slope of 46 mV dec(-1), and excellent stability for a 22-h chronopotentiometry test. In addition, the overpotential of our catalyst is much lower than that of RuO2, i.e., 20 mV lower at 50 mA cm(-2). This work demonstrates a new type of excellent OER catalyst with a hierarchical structure.