Influence of the calcination temperature and ionic liquid used during synthesis procedure on the physical and electrochemical properties of Ti/(RuO2)0.8-(Sb2O4)0.2 anodes

The development of synthesis methods to produce efficient anodes for wastewater treatment systems is an important industrial issue. Here, we describe the synthesis and the physical and electrochemical characterization of Ti/(RuO2)0.8-(Sb2O4)0.2 anodes prepared by thermal decomposition. The electrodes were prepared using three calcination temperatures (500, 550 and 600 °C) and using 2-hydroxyethylammonium acetate (2HEAA) and methyl-imidazolium hydrogensulfate ((HMIM)HSO4) ionic liquids (IL) as solvents for the precursors solutions. Both ionic liquids used were characterized in terms of water content and viscosity. The 2HEAA IL is almost 10 times more viscous than the (HMIM)HSO4 IL. The anodes developed were electrochemically characterized by cyclic voltammetry, morphology factor, electrochemical impedance spectroscopy and accelerated service lifetime tests. The electrodes synthesized using the 2HEAA IL have superior electrocatalytic properties and electrochemical stability than those made using the (HMIM)HSO4 IL. In addition, the anodes made using the 2HEAA IL as solvent have more homogenous surfaces and higher crystallinity degree than those made using the (HMIM)HSO4 IL. Among the studied calcination temperatures, combining 550 °C and the 2HEAA IL results in more compact and rough electrode surfaces with the highest electroactive areas and electrochemical stability. Thus, the temperature of 550 °C is suitable for the synthesis of mixed metal oxide (MMO) anodes. The electrodes synthesized using the 2HEAA IL are more efficient in the electrochemical oxidation of the Reactive Yellow 186 dye than those made using the (HMIM)HSO4 IL. Consequently, the viscosity of the IL used has great influence on the performance of the synthesized anodes. In addition, the high viscosity of the 2HEAA IL results in a lower number of calcinations steps to produce the anodes and, hence, lower production cost. Viscous ionic liquids are therefore promising for the production of MMO anodes via thermal decomposition methods.