High-Performance Ti/IrO₂–RhOx–Ta₂O₅Electrodes for Polarity Reversal Applications

Abstract

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.

Common Issues in Aeration System Choice for Flotation Wastewater Treatment

“…When a sacrificial anode is used, the anode dissolves forming metal hydroxides, and a process of electrocoagulation takes place. Iron and aluminum anodes are the most commonly used [18,36], however, zinc, copper [37,38] and dimensionally stable anodes made of coated metals such as titanium [39][40][41] are also used. The electrodes can be placed in the flotation cell horizontally (as shown in Figure 2) or vertically.…”

Scaling-Free Cathodes: Enabling Electrochemical Extraction of High-Purity Nano-CaCO3 and -Mg(OH)2 in Seawater

“…The second strategy is postprocessing. For instance, mechanical descaling, 17 acid pickling, 18 or electrode polarity reversal 19 has to be carried out to remove scale layers from cathodes, which increases operating cost, shortens electrode lifetime, and still interrupts reactions frequently. Essentially, these strategies only avoid the contact between hardness ions and cathodes or clean up the created scale layers but do not solve the problem of cathodic scaling.…”

Preparation of Ti/IrRuSnSbOx Electrodes by a Hydrosol Process for Efficient and Stable Chlorine Evolution Reaction

“…Preparation. Titanium sheet (Ti, 12.5 mm × 50 mm × 1 mm) as a substrate was sandpapered and etched according to the process parameters in ref 24. In order to fabricate the Ti/ IrRuSnSbO x electrodes by thermal decomposition, the precursor solutions with 0.5 M metal cations (Ir:Ru:Sn:Sb = 10:20:61:9) were prepared by two methods, first by the alcohol method utilizing isopropyl alcohol and the second by the hydrosol method.…”