Enhanced electrocatalytic performance for oxygen evolution reaction via active interfaces of Co 3 O 4 arrays@FeO x /Carbon cloth heterostructure by plasma-enhanced atomic layer deposition

Oxygen evolution reaction (OER) is a necessary procedure in various devices including water splitting and rechargeable metal-air batteries but required a higher potential to improve oxygen evolution efficiency due to its slow reaction kinetics. In order to solve this problem, a heterostructured electrocatalyst (Co O @FeO /CC) is synthesized by deposition of iron oxides (FeO ) on carbon cloth (CC) via plasma-enhanced atomic layer deposition, then growth of the cobalt oxide (Co O ) nanosheet arrays. The deposition cycle of FeO on the CC strongly influences the growth and distribution of Co O nanosheets and electronic conductivity of the electrocatalyst. Owing to the high accessible and electroactive areas and improved electrical conductivity, the free-standing electrode of Co O @FeO /CC with 100 deposition cycles of FeO exhibits excellent electrocatalytic performance for OER with a low overpotential of 314.0 mV at 10 mA cm and a small Tafel slope of 29.2 mV dec in alkaline solution, which is much better than that of Co O /CC (448 mV), and even commercial RuO (380 mV). This design and optimization strategy shows a promising way to synthesize ideally designed catalytic architectures for application in energy storage and conversion.