Surface microstructures and oxygen evolution properties of cobalt oxide deposited on Ir(111) and Pt(111) single crystal substrates

Abstract

We investigated the oxygen evolution reaction (OER) activity changes of cobalt oxide (CoOx) thin films on Ir(111) and Pt(111) substrates by repeated OER measurements in 0.1 M KOH. Atomic force microscopy and X‐ray photoelectron spectroscopy analysis of the as‐prepared CoOx/Ir(111) and CoOx/Pt(111) showed similar surface morphologies of the CoOx thin films and almost the same OER overpotentials, which were estimated to be around 430 mV. However, after three OER measurements, the overpotential of CoOx/Ir(111) decreased by 70 mV, whereas that of CoOx/Pt(111) increased slightly. Structural analysis showed that CoOx/Ir(111) revealed the island‐like nanostructures of CoOx dispersed on Ir(111) surface, accompanied by the generation of CoOOH. In contrast, for CoOx/Pt(111), the Pt(111) substrate remains covered by the CoOx thin film. The results suggest that the interaface at CoOx (CoOOH) nano‐islands and Ir(111) substrate are responsible for reducing the OER overpotential.

Suppressed Hydrogen Peroxide Generation and Enhanced Electrochemical Hydrogen Oxidation Activity for Tungsten-Oxide-Modified Platinum Surface Model Catalyst System

“…After subsequent cooling, the surface-cleaned Pt(111) substrate was transferred to the loadlock chamber. WO x was deposited onto the surface-cleaned Pt(111) through the reactive APD 23,24) of W under an O 2 partial pressure ( p(O 2 )) of 1 © 10 ¹1 and 1 © 10 ¹3 Pa. The arc voltage of the APD was fixed at 100 V. A metal W rod (diameter, 10 mm; 99.96%, Semicom Co., Ltd.) was used as a target for the APD.…”

Efficient Ozone Evolution Anode of Tantalum Nitride with Cubic Crystal Structure

“…In this study, we postulated a stacking structure of a surface Ta oxide layer on a Ta nitride thin film for effective O 3 evolution anodes and consequently synthesized Ta nitride thin films with various crystal structures on a Pt substrate using the reactive arc plasma deposition (APD) method under N 2 partial pressure. − The resulting crystal structures of the Ta nitrides have cubic, hexagonal, and mixed crystal structures depending on the APD conditions, particularly the deposition rates and thicknesses of the TaN thin films. The estimated O 3 evolution efficiency of the TaN thin film anode with a cubic crystal structure is highest in the potential region of 3.2–5.2 V, outperforming those of PbO 2 - and SnO 2 -based electrodes.…”

Suppression of Catalyst Layer Detachment by Interfacial Microstructural Modulation of the NiCo2O4/Ni Oxygen Evolution Electrode for Renewable Energy-Powered Alkaline Water Electrolysis

“…In particular, the slow kinetics of electrode reactions hinders the performance improvement of AWE. Consequently, active and durable catalysts have been intensively researched both for anodes − and cathodes. − Highly active nanostructured catalysts have been developed as anode catalysts for the oxygen evolution reaction (OER), represented by NiFe-layered double hydroxide (LDH). , Additionally, NiCo 2 O 4 (NCO) is a widely investigated OER catalyst for AWE due to its high activity, durability, and electronic conductivity. − For practical use, the NCO catalyst layer (CL) is generally formed by the coating-pyrolysis method on a high-surface-area Ni electrode such as mesh due to its low manufacturing cost and high scalability.…”