A comparative study on the Mn/TiO2-M(M = Sn, Zr or Al) Ox catalysts for NH3-SCR reaction at low temperature. Issue 10 (19th May 2018)

• Record Type: Journal Article
• Authors: Zhang, Yaping; Huang, Tianjiao; Xiao, Rui; Xu, Haitao; Shen, Kai; Zhou, Changcheng
• Is Part Of: Environmental technology. Volume 39:Issue 10(2018)
• Page Start: 1284
• Page End: 1294
• Publication Date: 2018-05-19
• Subjects: TiO2–SnO2 -- TiO2–ZrO2 -- TiO2–Al2O3 -- MnOx -- low-temperature SCR -- poisoning -- Ti-SnTi-Al; Environmental engineering -- Periodicals; Environmental protection -- Periodicals; 628.05
• DOI: 10.1080/21622515.2017.1329345
• Languages: English
• ISSNs: 0959-3330

Abstract

ABSTRACT: A series of TiO2 -M(M = Sn, Zr or Al) O x were prepared and manganese oxide (MnO x ) was supported on the carrier by the traditional impregnation method for low-temperature selective catalytic reduction (SCR) of NO x with ammonia as a reductant. The obtained catalysts were characterized by XRD, BET, high-resolution transmission electron microscope (HRTEM), H2 -TPR, NH3 -TPD, X-ray photoelectron spectroscopy (XPS) and in situ Fourier-transform infrared (FT-IR) and their catalytic activities for NO x reduction with NH3 in the presence of SO2 were investigated comparatively. The results showed that the highest NO x conversion of over 90% could be obtained with the Mn/Ti-Sn catalyst at a wide range of temperature window of 150–270°C. The combination of characterization techniques, such as BET, XRD and HRTEM, revealed that manganese oxides were well dispersed on Ti-Sn. H2 -TPR suggested that Ti-Sn and Ti-Zr supports could enhance the reduction ability of catalysts. Accordingly, Mn/Ti-Al exhibited worse activity at low temperature. XPS results were in good agreement with H2 -TPR results, and Mn/Ti-Sn had more surface-reducible species of Mn 4+ ions and more surface-adsorbed oxygen species, which was conducive to SCR reaction. The in situ FT-IR spectra of NH3 adsorption indicated that all the modified catalysts had more Lewis acid sites and the amide species at 1506 cm −1 had a certain influence on the catalytic reaction at low temperature. Mn/Ti-Zr showed a stronger resistance to SO2 but Mn/Ti-Al was affected more adversely and all the catalysts could not be restored to the initial catalytic activity after stopping feeding SO2 . NH3 -TPD revealed that the total acid amount of the Mn/Ti-Sn sample was larger than other samples, which indicated that the Ti-Sn solid solution could provide more surface acid sites over the catalyst.