Abstract:
This research aimed to study the effect of sulfuric acid treatment on the catalytic performance of WO3/TiO2 for the simultaneous removal of nitric oxide and toluene co-existing in an exhaust gas. The TiO2 support was treated with sulfuric acid aqueous solutions having concentrations of 0, 0.2 and 0.5 M before being used as catalyst support. The prepared catalysts were characterized by using ICP technique (ICP-OES Perkin Elmer Optima 7000DV), Nitrogen Physisorption, X-ray Diffraction (XRD), NH3 Temperature Programmed Desorption (NH3-TPD) and Pyridine Adsorption. Catalyst performance evaluations were divided into three systems. The first system was nitric oxide removal system by the selective catalytic reduction (SCR) reaction. The second system is the elimination of toluene through the oxidation. The third system was the simultaneous nitric oxide and toluene removal system (mixed system). The reaction was carried out in the reaction temperature range of 120 - 450 °C. It was found that WO3/TiO2 catalyst treated with 0.2 M sulfuric acid had the highest catalytic activity for the reduction of nitrogen oxide. The WO3/TiO2 catalyst treated and untreated with sulfuric acid had about the same performance for toluene removal but WO3/TiO2 catalyst treated with 0.5 M sulfuric acid had higher the amount of carbon dioxide formation. For the mixed system, it was found that the presence of toluene enhanced the nitric oxide reduction at high reaction temperature compared with the SCR system without toluene.