Novel eco-friendly method to prepare Ti/RuO2–IrO2 anodes by using polyvinyl alcohol as the solvent

Electrochemical oxidation processes are promising solutions for wastewater treatment due to their high efficiency, effortless control, and versatility. Mixed metal oxides anodes are particularly attractive due to their low cost and specific catalytic properties. Here, we report the synthesis of a new Ti/RuO2-IrO2 anode fabricated through an innovative eco-friendly methodology using polyvinyl alcohol (PVA) as the solvent. Comparative anodes were also prepared by the conventional method of polymeric precursors. For both methods, anodes were calcined at 300, 400, and 500 °C. X-ray diffraction data confirmed the formation of RuO2 and IrO2 in the rutile-type structure for all conditions. Moreover, compared to conventional polymeric precursor method, PVA-made anode obtained at 300 °C presented increased voltammetric charge (210%), besides reduced charge-transfer resistance (1.8-fold lower). Electrochemical degradation of the Reactive Blue 21 dye showed that the PVA-made Ti/RuO2-IrO2 anode has the highest degradation efficiency, and its kinetic rate constant is until 2 times greater than the conventional anode. Besides, due to rougher and more compact surfaces, the better adhesion of the film observed for the PVA-made anodes, the accelerated service lifetime of the anode was prolonged 4.3-fold. [Display omitted] •The green method developed employing PVA as solvent improves RuO2-IrO2 anode lifetime.•The most suitable calcination temperature was proven to be 300 °C.•Charge-transfer resistance is 1.8-fold lower than the anodes made by Pechini method.•Anode made using PVA is the most efficient towards reactive blue 21 dye oxidation.