Plasma enhanced atomic-layer-deposited nickel oxide on Co3O4 arrays as highly active electrocatalyst for oxygen evolution reaction

Energy storage technologies are developed over the past decades, such as metal-air batteries. The large-scale application of these devices is finite due to slow kinetics of the oxygen evolution reaction (OER). In order to solve this issue, plasma enhanced atomic layer deposition (PE-ALD) is used to synthesize high performance nano oxide (NiOx@Co3O4/CC) electrocatalyst for OER applications. Herein, the cobalt oxide (Co3O4) nanowire arrays are grown on oxygen plasma-treated carbon-cloth (CC) and then a thin layer (similar to 1.2 nm) of nickel oxide (NiOx) is deposited on the Co3O4/CC through PE-ALD method. The electrocatalyst of two transition metal oxides plays a leading role in improving the OER performance and stability. The overpotential for OER of NiOx@Co3O4/CC electrocatalyst is 360 mV at 10 mA cm(-2), which is much lower than that of Co3O4/CC (420 mV) and comparable to commercial RuO2 (350 mV) electrocatalyst. Moreover, the stability of NiOx@Co3O4/CC electrocatalyst is also improved, which only 8.85% of the initial current is loss after 40,000 s. It is demonstrated that PE-ALD synthesis method provides a facile approach to fabricate highly efficient nano-oxide electrocatalysts for OER in energy storage devices.