Atomic layer deposition for efficient oxygen evolution reaction at Pt/Ir catalyst layers

Abstract

We provide a direct comparison of two distinct methods of Ti felt surface treatment and Pt/Ir electrocatalyst deposition for the positive electrode of regenerative fuel cells and vanadium–air redox flow batteries. Each method is well documented in the literature, and this paper provides a direct comparison under identical experimental conditions of electrochemical measurements and in identical units. In the first method, based on classical engineering, the bimetallic catalyst is deposited by dip-coating in a precursor solution of the salts followed by their thermal decomposition. In the alternative method, more academic in nature, atomic layer deposition (ALD) is applied to the felts after anodization. ALD allows for a controlled coating with ultralow noble-metal loadings in narrow pores. In acidic electrolyte, the ALD approach yields improved mass activity (557 A·g−1 as compared to 80 A·g−1 at 0.39 V overpotential) on the basis of the noble-metal loading, as well as improved stability.

Applications of Atomic Layer Deposition in Design of Systems for Energy Conversion

“…[ 88 ] The same type of the composites was tested as the cathode material in fuel cells and vanadium‐air batteries. [ 89 ] Nanostructured Ir/TiO 2 electrodes prepared by a deposition of Ir‐films onto the surface of highly ordered TiO 2 nanotubes grown from Ti‐foils from ((EtCp)Ir(CHD)) and ozone at 220 °C exhibited excellent OER properties. The overpotential of OER in 0.1 m H 2 SO 4 was as low as 240 mV versus RHE at current density 10 mA cm −2 and mass activity 200 A g −1 at 340 mV with catalyst loading 160 µg cm −2 .…”

Electrochemical Activation of Atomic-Layer-Deposited Nickel Oxide for Water Oxidation

“…This feature not only increases the concentration of active sites for catalytic reactions but also promotes efficient mass transport of reactants . In addition, the potential of ALD to tune the chemical composition and thickness of films enables the improvement of their performance and stability for OER. − Accordingly, the method has gained significant attention in the development of electrocatalysts for OER. − In previous work, we have shown that ALD enables digital control over the stoichiometry of cobalt phosphate films and that this approach leads to a deeper understanding of their activation mechanism and performance. Moreover, Mattelaer et al demonstrated the feasibility of producing active manganese oxide catalysts through ALD.…”