Water splits into hydrogen and oxygen electrochemically is one of the most promising strategies for the utilization and storage of solar energy. However, oxygen evolution reaction (OER) with sluggish kinetics hinders its larger-scale application. NiFe-based catalysts are one of the most efficient oxygen evolution catalysts (OECs). High-valence Ni is considered as active site or conductive framework in NiFe-based OECs. However, the oxidation of Ni usually be hindered in the presence of Fe. This paper describes an effective strategy to produce NiFe (oxy)hydroxide with easily oxidized Ni and hierarchical nanosheet structure as the most efficient OEC. High valence Ni may provide frameworks with good conductivity and facilitate OER in Fe active site. In addition, the hierarchical structure can increase the electrochemical surface area, resulting in more active sites for OER. The as-prepared Fe-O-Ni(OH)2 supported on nickel foam just need the overpotential of 185, 220 and 261 mV to drive current density of 10, 100 and 500 mA cm2, respectively. It also shows excellent stability at the current density of 100 and 500 mA cm2 for 50 hours.
Read more in our recent publication:
J. Mater. Chem. A 2018, in press, DOI: 10.1039/C8TA04721A