Oxygen evolution at IrO2-modified Ti anodes prepared by a simple galvanic deposition method

摘要

Highly active IrO2-modified Ti anodes have been prepared via a simple galvanic deposition process whereby a Ti substrate (freshly etched in boiling HCl containing fluoride ions) has been treated with an Ir(IV) solution, resulting in the reduction-deposition of Ir(IV) as metallic Ir on the surface of the Ti substrate with the simultaneous oxidation of nearby freshly etched Ti sites. Cyclic voltammetry of the resulting (Ir-TiO2)/Ti electrode in acidic solutions revealed features of IrO2 formation at positive applied potential values during continuous potential cycling. SEM micrographs showed good Ir dispersion on the Ti substrate, while EDS and XPS analysis of the deposits provided direct evidence for Ir and IrO2 presence on the surface of the electrodes. These electrodes, when tested as oxygen evolution reaction (OER) anodes by slow potential sweep voltammetry and constant potential amperometry, exhibited one of the highest mass specific activities for OER (560 mA mg(Ir)(-1)) reported for IrO2 anode materials.