Biomaterial Database

Catalytic Oxidation of NO over MnOx-CeO₂ and MnOx-TiO₂ Catalysts. 2016

Xiaolan Zeng, and Xiaoyue Huo, and Tianle Zhu, and Xiaowei Hong, and Ye Sun

School of Space and Environment, Beihang University, Beijing 100191, China. xlzeng@buaa.edu.cn.

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 MnOx over 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 MnOx active sites from being poisoned. In contrast, MnOx active 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 NOx than the MnOx-TiO₂ catalyst, especially after SO₂ poisoning.

UI	MeSH Term	Description	Entries
D009569	Nitric Oxide	A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.	Endogenous Nitrate Vasodilator,Mononitrogen Monoxide,Nitric Oxide, Endothelium-Derived,Nitrogen Monoxide,Endothelium-Derived Nitric Oxide,Monoxide, Mononitrogen,Monoxide, Nitrogen,Nitrate Vasodilator, Endogenous,Nitric Oxide, Endothelium Derived,Oxide, Nitric,Vasodilator, Endogenous Nitrate
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D010087	Oxides	Binary compounds of oxygen containing the anion O(2-). The anion combines with metals to form alkaline oxides and non-metals to form acidic oxides.	Oxide
D002384	Catalysis	The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.	Catalyses
D002563	Cerium	An element of the rare earth family of metals. It has the atomic symbol Ce, atomic number 58, and atomic weight 140.12. Cerium is a malleable metal used in industrial applications.
D000327	Adsorption	The adhesion of gases, liquids, or dissolved solids onto a surface. It includes adsorptive phenomena of bacteria and viruses onto surfaces as well. ABSORPTION into the substance may follow but not necessarily.	Adsorptions
D013499	Surface Properties	Characteristics or attributes of the outer boundaries of objects, including molecules.	Properties, Surface,Property, Surface,Surface Property
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures
D014025	Titanium	A dark-gray, metallic element of widespread distribution but occurring in small amounts with atomic number, 22, atomic weight, 47.867 and symbol, Ti; specific gravity, 4.5; used for fixation of fractures.
D014961	X-Ray Diffraction	The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Xray Diffraction,Diffraction, X-Ray,Diffraction, Xray,Diffractions, X-Ray,Diffractions, Xray,X Ray Diffraction,X-Ray Diffractions,Xray Diffractions