Direct MOCVD Growth of Iron Oxide on Three‐Dimensional Nickel Foam as Electrode for the Oxygen Evolution Reaction

Abstract

Iron oxide thin films were grown directly on three-dimensional nickel foam via metalorganic chemical vapor deposition (MOCVD) in the temperature range of 250-450°C using Fe(CO) 5 as precursor. Iron oxide (α-Fe 2 O 3) films were formed at low substrate temperatures (250-350°C), whereas the additional growth of an underlying NiO film occurred at substrate temperatures above 350°C. The electrochemical activities of the asformed binder-free and noble metal-free electrodes were tested for the oxygen evolution reaction (OER) in alkaline media. An overpotential reduced by 250 mV at a current density of 50 mA cm À 2 and a lower Tafel slope of 55 mV dec À 1 compared to bare nickel foam were found for the best-performing electrocatalyst, while the long-term stability of the as-formed electrodes was proven by chronopotentiometry. The surface morphology of the iron oxide films was characterized by scanning electron microscopy, whereas the crystallographic phase as well as the elemental composition were determined by X-ray diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry in the pre-and the post-catalytic state.

The Effect of the Degree of Fluorination on the MOCVD Growth of Cobalt Oxide Thin Films using Co(II) Acetylacetonate Complexes

“…MOCVD deposition studies were performed using a home‐made low‐pressure reactor [29] at 500 °C on Al 2 O 3 (0001), Si(001) and Pt substrates with synthetic air as oxidizer and carrier gas. 0.3 mmol precursor were used for each deposition run.…”

Hydrogen production by traditional and novel alkaline water electrolysis on nickel or iron based electrocatalysts

“…Stienen et al utilized the direct metalorganic chemical vapor deposition (MOCVD) method to deposit a coating layer of a-Fe 2 O 3 to nickel foam (Fe 2 O 3 @NiF-450) with great uniformity by oxidizing and decomposing Fe(CO) 5 at a high temperature of 450 1C. 104 This material was advantageous due to its three-dimensional framework, which allowed greater contact between the a-Fe 2 O 3 and the electrolyte. As a result, when tested in 1 M KOH, it was found to have an OER overpotential of 370 mV (@ 10 mA cm À2 ) and a Tafel slope of 55 mV dec À1 .…”