Atomic layer deposition of iron oxide on a porous carbon substrate via ethylferrocene and an oxygen plasma

Abstract Ethylferrocene, a novel precursor for atomic layer deposition (ALD) of iron oxide, was investigated using an oxygen plasma co-reactant. Iron oxide deposition showed a saturating growth rate of 0.1 A/cycle in the temperature range of 150 °C to 250 °C. The iron oxide coating was subsequently deposited on a porous gas diffusion layer (GDL) for use as an air electrode in a zinc-air battery. X-ray microanalysis confirmed deep penetration of the iron oxide into the porosity of the GDL, with a lower substrate temperature providing deeper coverage. Transmission electron microscopy revealed that a uniform ~10 nm thick iron oxide coating encased the GDL particles. Electron diffraction and X-ray photoelectron spectroscopy identified the iron oxide film as α-Fe2O3. Electrochemical characterization of the ALD-coated GDL showcased promising catalytic activity towards the oxygen evolution reaction.