Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
The effects of promoters on the sulfur resistance of nox storage/reduction catalysts : a density functional theory investigation
Download
index.pdf
Date
2011
Author
Koşak, Rukan
Metadata
Show full item record
Item Usage Stats
202
views
83
downloads
Cite This
High fossil fuel consumption in transportation and industry results in an increase of the emission of green-house gases. To preserve clean air, new strategies are required. The main intention is to decrease the amount of CO2 emission by using lean-burn engines while increasing the combustion efficiency and decreasing the fuel consumption. However, the lean-burn engines have high air-to-fuel ratio which complicates the reduction of the oxides of nitrogen, NOx . The emission of these highly noxious pollutants, NOx , breeds both environmental and health problems. Thus, new catalytic strategies have been steadily developed. One of these strategies is the NOx storage and reduction (NSR) catalysts. Since the reduction of the NOx under excess oxygen condition is very difficult, the NSR catalysts store the NOx until the end of the lean phase that is subsequently alternated with the rich-fuel phase during which the trapped NOx is released and reduced. To develop NSR technology, different storage materials, the coverage of these metals/metal-oxides, support materials, precious metals, temperature, etc. have been widely investigated. In this thesis, the (100) surface of BaO with dopants (K, Na, Ca and La), (100) and (110) surfaces of Li2O, Na2O and K2O are investigated as storage materials. In addition, alkali metal (Li, Na and K) loaded (001) surface of TiO2 (titania) anatase is investigated as a support material for the NOx storage and reduction catalysts. The main aim is to increase the sulfur resistance. The introduction of the dopants on the BaO (100) surface has increased the stability of the NO2 . The combination of local lattice strain and different oxidation state, which is obtained by the La doped BaO (100) surface, benefit both NO2 adsorption performance and sulfur tolerance. The binding energies of NO2 adsorption configurations over the alkali metal oxide (100) and (110) surfaces were higher than the binding energies of SO2 adsorption configurations. The stability of all of NO2 adsorption geometries on the alkali metal-loaded TiO2 (001) surface were higher than the stability of SO2 adsorption geometries. Increasing basicity enhanced the adsorption of NO2 molecule.
Subject Keywords
Air
URI
http://etd.lib.metu.edu.tr/upload/12613442/index.pdf
https://hdl.handle.net/11511/20675
Collections
Graduate School of Natural and Applied Sciences, Thesis
Suggestions
OpenMETU
Core
Investigation of Turkey's carbon dioxide problem by numerical modeling
Can, Ali; Tokdemir, Turgut; Department of Engineering Sciences (2006)
CO2 emission is very important, because it is responsible for about 60% of the "Greenhouse Effect". The major objectives of this study were to prepare a CO2 emission inventory of Turkey based on districts and provinces by using the fuel consumption data with respect to its sources, to find the CO2 uptake rate of forests in Turkey based on provinces and districts, and to estimate the ground level concentration of CO2 across Turkey using U.S. EPA's ISCLT3 model for the preparation of ground level concentratio...
Simulating the effects of deep saline aquifer properties for CO2 sequestration
Basbug, B.; Gumrah, F.; Oz, B. (2007-10-01)
CO2 is one of the hazardous greenhouse gases causing significant changes to the environment. The sequestering of CO2 in a suitable geological media can be a feasible method to avoid the negative effects of CO2 emissions into the atmosphere. A numerical model was developed regarding CO2 sequestration in a deep saline aquifer. A compositional numerical model using CMG software (GEM) was employed to study the ability of the selected aquifer to accept and retain large quantities of CO2 injected in a supercritic...
A geochemical equilibrium modeling approach to assessing soil acidification impacts due to depositions of industrial air emissions
Ünlü, Kahraman; Soyupak, S; Yurteri, C (1999-07-01)
Soil acidification impacts arising from depositions of industrial air emissions may become a serious environmental concern. Currently, in the literature quantitative mechanistic modeling and the experimental acid neutralizing capacity (ANC) approach and a qualitative evaluation approach classifying soils into various levels of sensitivity to acid additions have been reported to assess the long-term soil acidification impacts due to industrial air emissions. Another alternative quantitative approach proposed...
Effect of support material in nox storage/reduction catalysts
Hummatov, Ruslan; Toffoli, Hande; Toffoli, Daniele; Department of Physics (2010)
Energy need in transportation and industry is mainly met by fossil fuels. This causes consumption of resources and some environmental problems. Diesel and gasoline engines are developed to consume fuel efficiently in vehicles. Since these engines work in a low fuel to air ratio, it becomes difficult to reduce nitrogen oxide emission. For this reason NO x storage/reduction (NSR) catalysts have been developed. While engines are operating under lean conditions alkaline or alkaline-earth component of NSR cataly...
Investigation of emission factors of non-methane hydrocarbons some widely used passenger cars in Turkey
Önoğlu, İrem; Atımtay, Aysel; Department of Environmental Engineering (2004)
The objectives of this study are to measure the non-methane volatile organic carbon (NMVOC's) emissions from passenger cars in Turkey having gasoline engines, to determine emission factors of these vehicles for BTEX compounds and comparison of emission factors obtained in this study with the emission factors of the other countries. This study was conducted in two parts: The first part was to determine the categories of passenger cars widely used in Turkey, and also to determine the average carbon monoxide (...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
R. Koşak, “ The effects of promoters on the sulfur resistance of nox storage/reduction catalysts : a density functional theory investigation,” M.S. - Master of Science, Middle East Technical University, 2011.