title: Catalytic Oxidation of NO over MnOx-CeO₂ and MnOx-TiO₂ Catalysts.
abstract: A series of MnOx-CeO₂ and MnOx-TiO₂ catalysts were prepared by a homogeneous precipitation method and their catalytic activities for the NO oxidation in the absence or presence of SO₂ were evaluated. Results show that the optimal molar ratio of Mn/Ce and Mn/Ti are 0.7 and 0.5, respectively. The MnOx-CeO₂ catalyst exhibits higher catalytic activity and better resistance to SO₂ poisoning than the MnOx-TiO₂ catalyst. On the basis of Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and scanning transmission electron microscope with mapping (STEM-mapping) analyses, it is seen that the MnOx-CeO₂ catalyst possesses higher BET surface area and better dispersion of MnOxover the catalyst than MnOx-TiO₂ catalyst. X-ray photoelectron spectroscopy (XPS) measurements reveal that MnOx-CeO₂ catalyst provides the abundance of Mn3+and more surface adsorbed oxygen, and SO₂ might be preferentially adsorbed to the surface of CeO₂ to form sulfate species, which provides a protection of MnOxactive sites from being poisoned. In contrast, MnOxactive sites over the MnOx-TiO₂ catalyst are easily and quickly sulfated, leading to rapid deactivation of the catalyst for NO oxidation. Furthermore, temperature programmed desorption with NO and O₂ (NO + O₂-TPD) and in situ diffuse reflectance infrared transform spectroscopy (in situ DRIFTS) characterizations results show that the MnOx-CeO₂ catalyst displays much stronger ability to adsorb NOxthan the MnOx-TiO₂ catalyst, especially after SO₂ poisoning.
authors.affiliation: School of Space and Environment, Beihang University, Beijing 100191, China. xlzeng@buaa.edu.cn.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Zeng
authors.affiliation: School of Space and Environment, Beihang University, Beijing 100191, China. xyhuo1123@163.com.
authors.forename: Xiaoyue
authors.initials: X
authors.lastname: Huo
authors.affiliation: School of Space and Environment, Beihang University, Beijing 100191, China. zhutl@buaa.edu.cn.
authors.forename: Tianle
authors.initials: T
authors.lastname: Zhu
authors.affiliation: School of Space and Environment, Beihang University, Beijing 100191, China. hongxiao86@126.com.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Hong
authors.affiliation: School of Space and Environment, Beihang University, Beijing 100191, China. suny@buaa.edu.cn.
authors.forename: Ye
authors.initials: Y
authors.lastname: Sun
mesh_terms: D000327:Adsorption; D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D013499:Surface Properties; D013696:Temperature; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D017895:Manganese Compounds; D010087:Oxides; C009495:titanium dioxide; D002563:Cerium; D009569:Nitric Oxide; C030583:ceric oxide; C027424:manganese oxide; D014025:Titanium
keywords: MnOx–CeO2; MnOx–TiO2; NO; SO2; catalytic oxidation