High-Performance Ti/IrO 2 –RhOx–Ta 2 O 5 Electrodes for Polarity Reversal Applications

Electrode polarity reversal has been widely employed to inhibit membrane fouling and induce scale detachment during electrodialysis and electrochemical precipitation, respectively. However, frequent polarity reversal shortens the lifetime of traditional dimensionally stable anodes. In this study, a novel titanium electrode that employed a ternary iridium, tantalum, and rhodium oxide mixture (IrO 2 –RhOx–Ta 2 O 5 ) as an active electrocatalyst film was investigated for polarity reversal applications. It was found that the Ti/IrO 2 –RhOx–Ta 2 O 5 electrode with an Ir/Rh/Ta molar ratio of 3:3:4 had a service lifetime of 1030 h in a 20 g L –1 Na 2 SO 4 solution at a current density of 2000 A m –2 and a polarity reversal frequency of 12 h –1 . In contrast, a Ti/IrO 2 –Ta 2 O 5 electrode with an Ir/Ta molar ratio of 6:4 under the same conditions exhibited a service lifetime of only 275 h. Physicochemical characterization revealed that the IrO 2 –RhOx–Ta 2 O 5 film has a compact microstructure, solid solution characteristics, and contains both Rh 3+ and Rh 4+ which contributes to the stability during polarity reversal. Moreover, the Ti/IrO 2 –RhOx–Ta 2 O 5 electrode showed better chlorine evolution performance than the Ti/IrO 2 –Ta 2 O 5 electrode.