Ni(OH)2NiOOH 2D-nanosheets tailored with FeOOH nanorods: A synergy of morphological engineering towards bifunctional overall water splitting

Abstract

Oxygen evolution reaction (OER) is the bottleneck for effective overall water splitting owing to its sluggish reaction kinetics. Metal oxyhydroxides are a significant class of electrocatalysts that demonstrate remarkable activity and stability toward the oxygen evolution reaction. A facile one-pot hydrothermal synthesis is demonstrated in this study to obtain the heterostructured NiFe-oxyhydroxide electrocatalyst. FeOOH nanorods are decked over the 2D Ni(OH)2NiOOH nanosheets to form the Ni(OH)2NiOOH/FeOOH heterostructure. The prepared Ni(OH)2NiOOH/FeOOH electrocatalyst demands a minimal OER overpotential of 209 mV to reach a current density of 10 mA cm- 2, which is relatively smaller than the commercial RuO2. Moreover, the NiFeoxyhydroxide also exhibits remarkable activity towards hydrogen evolution reaction by demanding a minimal overpotential of 118 mV that is relatively lower than the commercial Pt/C to obtain a current density of 10 mA cm-2. With the implication of prepared Ni(OH)2NiOOH/FeOOH both as anode and cathode, the fabricated electrolyzer demonstrates a minimal cell voltage of 1.52 V to attain a current density of 10 mA cm-2 and displays an extended stability for a period of 50 h.