Effect of H2O and SO2 on the activity of Pd/TiO2 catalysts in catalytic reduction of NO with methane in the presence of oxygen

Karakaş, Gürkan
Bryan, Kimberly A.
Ozkan, Umit S.
Effect of H2O and SO2 on the NO reduction activity of the Pd/titania catalysts was examined in the NO+CH4+O-2 reaction. Steady-state and transient response experiments were performed using a tubular flow reactor. Isotopically labeled methane, (CH4)-C-13, was used in studying the transient behavior of the catalytic system. Reactor effluents were analyzed by using gas chromatography, mass spectrometry, and chemiluminescense techniques. Steady-state reaction experiments showed that the catalyst has a high activity for reduction of NO over a wide oxygen concentration range (0-9800 ppm at 500 degrees C). Higher N-2 selectivities (less NH3) and higher methane conversion values were obtained at higher O-2 concentrations. Experiments also showed that NO conversion was not affected by the presence of water (up to 6%), and higher nitrogen selectivities were obtained at higher H2O concentrations in the feed. On the other hand, significant and irreversible loss of activity was observed in the presence of SO2. The reaction experiments indicated the formation of SO3 and H2S over the catalyst. The post-reaction XPS analysis of the catalyst samples showed that sulfate species were formed on the surface and that the surface palladium was completely converted to pd(2+) State after being exposed to SO2.
Catalysis Today


Characterization and temperature-programmed studies over Pd/TiO2 catalysts for NO reduction with methane
Ozkan, Umit S.; Kumthekar, Mahesh W.; Karakaş, Gürkan (1998-02-02)
Characterization and temperature-programmed studies were performed over Pd/titania catalysts to examine their activity in the reduction of NO with methane. The catalyst was prepared using a wet impregnation technique and Pd-acetate was used as a precursor for palladium. Techniques such as BET surface area measurements, X-ray diffraction, laser Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy were used for the characterization of the catalyst before and after the reactio...
Effect of H2O TEOT ratio on photocatalytic activity of sol gel derived TiO2 powder
Lütfi, Ağartan; Kapusuz, Derya; Park, Jongee; Öztürk, Abdullah (2013-01-01)
Effect of solvent choice on cellulose acetate membrane fabrication by phase inversion and deacetylation by alkaline hydrolysis
Tekin, Fatma Seden; Çulfaz Emecen, Pınar Zeynep; Department of Chemical Engineering (2022-8)
In this study, the effect of solvent choice on cellulose acetate (CA) membrane morphology and performance was investigated to relate this to the thermodynamics and kinetics of phase inversion. Three different solvent systems were used, which are dimethyl sulfoxide (DMSO), the mixture of DMSO: acetone (DA) and DMSO: acetic acid (DHAc) in the ratio of 1:1. Water was used as non-solvent. Acetone and acetic acid were chosen due to their similar solvent quality for cellulose acetate based on Hansen solubility pa...
Effect of sodium carbonate on carbothermic formation of hexagonal boron nitride
Akyıldız, Uğur; Sevinç, Naci; Department of Metallurgical and Materials Engineering (2010)
Effect of Na2CO3 on formation of hexagonal boron nitride (h-BN) by carbothermic method has been studied by subjecting B2O3-C and Na2CO3-added B2O3-C mixtures to N2 (g) atmosphere. Na2CO3 amount in the mixtures was changed in the range of 0-40 wt. %. Time and temperature were used as experimental variables. Reaction products were analyzed by XRD and scanning electron microscope. Na2CO3 was found to increase both the amount and the particle size of h-BN similar to CaCO3 [1]. Na2CO3 was found to be less effect...
KOCAK, HI; ARAS, L (Elsevier BV, 1990-07-01)
The solution behaviour of Na, Ba, Zn and Al ionomers of methyl methacrylate-methacrylic acid copolymer (P(MMA-MAA)) with different ion contents has been studied by viscosity and dipole moment measurements. Two solvents with different character are chosen for viscosity measurements: dioxane (ε = 2.22) and acetone (ε = 20.7). The expected polyelectrolyte behaviour of the ionomers in acetone is reflected by the viscometric measurements. Mean squared dipole moment 〈μ2〉 values are calculated over a temperature r...
Citation Formats
J. MITOME, G. Karakaş, K. A. Bryan, and U. S. Ozkan, “Effect of H2O and SO2 on the activity of Pd/TiO2 catalysts in catalytic reduction of NO with methane in the presence of oxygen,” Catalysis Today, pp. 3–11, 1998, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36377.