IrO₂-decorated Titania Nanotubes as Oxygen Evolution Anodes

• DOI: 10.20944/preprints202505.0028.v1
• Publication Date: 2025-05-06T02:05:05Z
• Authors: Aikaterini Touni; Effrosyni Mitrousi; Patricia Carvalho; Maria Nikopoulou; Eleni Pavlidou; Dimitra A. Lambro...; Sotiris Sotiropoulos
• Keywords: Oxygen evolution

In this work we have used both plain titania nanotubes, TNTs, and their reduced black analogues, bTNTs, that bear metallic conductivity (prepared by solid state reaction of TNTs with CaH2 at 5000C for 2 h), as catalyst supports the oxygen evolution (OER). Ir has been subsequently deposited on them galvanic replacement electrodeposited Ni Ir(IV) chloro-complexes; was followed electrochemical anodization to IrO2. By carrying out preparation in either two or one steps, were able produce close-packed open-structure respectively. former case, larger than 100 nm aggregates finally formed top face nanotubes (leading partial full surface coverage); latter nanoparticles smaller obtained, some located inside pores which retained a porous structure. The electrocatalytic activity IrO2 supported bTNTs towards OER is superior its performance comparable better similar electrodes reported literature (overpotential η=240 mV 10 mA cm-2; current density 70 cm-2 mass specific 258 mgIr-1 η=300 mV). Furthermore, these demonstrated good medium-term stability, maintaining stable 72 h cm⁻2 acid.