Influence of Synthesis Temperature on MnOx/TiO2 SCR DENOx Catalyst Prepared with Acidolysis Residue

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This paper focused on MnOx/TiO2 SCR DENOx catalytic materials prepared with acidolysis residue (a solid waste which was generated during the sulfate process of the titanium oxide industry), and investigated the influence of synthesis temperature on catalytic properties and microstructure of the catalytic materials. Two different synthesis temperatures including ambient temperature and 80 ℃ were employed to prepare the catalytic materials. The modifications of textural, surface properties and catalytic activity of catalyst prepared at different temperatures were compared. Results showed that the catalyst prepared by precipitation method at room temperature (ammonia-hydrogen peroxide was used as precipitant and the calcination temperature is 250 ℃), leads to a higher NOx conversion rate. The NOx conversion at 100 ℃ is 80%, even 95% at 130 ℃. Results from XRD analysis indicate that the catalyst synthesized at room temperature results in a less sharp peak of Mn3O4. The active substances of manganese oxides are highly dispersed on the surface of the catalytic materials in amorphous state. Furthermore, H2-TPR demonstrates that the catalyst synthesized at room temperature has a higher redox activity and the MnO2 phase occupies the leading position of MnOx, which contributes to the excellent NOx conversion rate of the catalytic.