Ultra-fast synthesis of Ti/Ru_0.3Ti_0.7O₂ anodes with superior electrochemical properties using an ionic liquid and laser calcination

Abstract

Here, we combine CO₂ laser heating and an ionic liquid solvent (i.e., methylimidazolium hydrogensulfate HMIM⁺ HSO₄^–) as an innovative route to produce Ti/Ru_0.3Ti_0.7O₂ anodes. For comparison purposes, the anodes were also prepared using conventional thermal treatment (in a furnace), and by the standard polymeric precursor method (also known as the Pechini method). For the laser heating, the anodes were heated at a power density of 0.4 W mm⁻² up to 550 °C and kept at this temperature for 40 s, followed by instantaneous cooling. Using these conditions, the total time spent to produce an anode (considering cooling) is just 9.7 min. It represents a remarkable reduction in 446-fold and 359-fold when compared with the conventional heating for Pechini and IL methods, respectively. The laser-prepared anodes presented an increase of 63.4% and 53.8% in the voltammetric charge, while the charge transfer resistance decreases 9.6-fold and 17.3-fold using IL and Pechini methods, respectively, when compared with their correspondent furnace-made ones. Finally, superior electrocatalytic activity toward the removal of the model pollutant atrazine is observed for the laser-prepared anodes. The anode produced using laser and the IL method is the most efficient, removing 81% of atrazine in 60 min, and presents the highest kinetic rate (0.062 min⁻¹) at the lowest energy consumption (0.179 kWh L^–1). The excellent electrocatalytic response of the anodes innovatively synthesized in this study characterizes them as an encouraging advance in the search for efficient materials to be applied in the electrochemical oxidation of organic compounds.