Mixed Oxides Issued from Hydrotalcite Precursors for Toluene and CO Total Oxidation: Comparison of Preparation Method

Catalytic total oxidation is an effective technique for the treatment of industrial VOCs. This emission is generally accompanied by the presence of other products like CO, NO_x or other VOC. In this paper, the development of catalysts for the total oxidation of CO and toluene mixture is performed. For this study, Mg₆Al₂HT hydrotalcites precursors were synthesized by three different methods: co-precipitation, microwaves and ultrasound assisted method. Hydrotalcite precursors have been used in order to develop mixed oxides after calcination for the catalytic oxidation test. Hydrotalcite structure as well as the mixed oxides obtained after calcination was studied, by several techniques: XRD, TEM, DTA/TG, BET, N₂ sorption, H₂-TPR. The physico chemical studies revealed modification in the structural characteristics (surface area, porosity) as well as in reducibility properties of the formed mixed oxides. The nanocatalyst issued from microwaves synthesis was the most active in these studied reactions for the total oxidation of the mixture. Moreover, addition of CO on the reaction mixture allows obtaining a beneficial effect on the toluene oxidation.