Density functional theory investigation of noble metal reduction agents on Gamma-Al2O3 in NOx storage/reduction catalysis /

Download

index.pdf

Date

2011

Author

Artuç, Züleyha

Metadata

Show full item record

Item Usage Stats

67
views

109
downloads

Pollution from automobile exhaust is one of the most major environmental problems because of increasing usage of engine technologies. Diesel and lean burn gasoline engines operate under oxygen rich (lean) conditions and they emit harmfull gases to the atmosphere (CO,CO2, NO, NO2). The control of NOx emission from exhaust has become a challenging issue in engine industry because of the worldwide environmental regulations. Therefore lean-burn NOx emission control technologies have been developed to reduce emission of harmfull gases from exhausts, and the NOx storage/reduction (NSR) catalysts is one of the most promising candidates to reduce the pollution caused by lean-burn engines. In NSR systems, NO from the emission is first oxidized to NO2 over noble metal sites (Pt, Rh, Pd) during lean-burn engine operation. After that NO2 is stored as nitrites and nitrates in alkali earth oxides (BaO,MgO, CaO) particles or monolayer which is well dispersed on a substrate (Gamma-Al2O3, TiO2, SiO2). Finally, stored NOx compound are broken into N2 and O2 on noble metal sites. The Pt/BaO/Gamma-Al2O3 system is one of the most popular subjects in literature both experimentally and theoretically since this system is known to be catalytically more active and e cient in interactions between NOx and Pt-BaO components are still not clearly explained. For this reason, in this thesis, the interaction between catalytic redox components, Pt and Rh, and the support material Gamma-Al2O3 and the e ects of Pt and Rh in atomic and diatomic clusters forms on the adsorption of the NO2 molecule on the Gamma-Al2O3(100) surface have been investigated by using density functional theory (DFT).

Subject Keywords

Density matrices.

URI

http://etd.lib.metu.edu.tr/upload/12613756/index.pdf
https://hdl.handle.net/11511/20771

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Estimation of diffuse solar irradiation and its effects on PV power plant production at METU NCC Kavas, Genco; Taylan, Onur; Sustainable Environment and Energy Systems (2019-8) Excess amount of greenhouse gas (GHG) emission is the main reason of global warming. Renewable energy systems are one possible way to decrease GHG emission and solar energy is one of options; however, fluctuations on solar energy production is one of the main drawbacks. Accurate estimation of energy production from a solar power plant, such as PV-based plant is important to satisfy energy demand successfully. To be able to estimate energy production in advance, solar energy incident on PV modules should be ...
The effects of promoters on the sulfur resistance of nox storage/reduction catalysts : a density functional theory investigation Koşak, Rukan; Toffoli, Daniele; Toffoli, Hande; Department of Chemistry (2011) 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...
Wash-Coat Development for Lean-Burn Engine-Exhaust Aftertreatment: Incorporation of Binder to Pd Supported on Sulfated Zirconia Majumdar, Sreshtha Sinha; Çelik, Gökhan; Ozkan, Umit S. (null; 2015-07-19) As the environmental regulations are getting more stringent, it is of great importance to develop a catalytic aftertreatment system for natural gas-fired lean-burn engines to reduce the emissions of nitrogen oxides (NOx), unburned hydrocarbons (CH4, C2H6, and C3H8) and carbon monoxide efficiently. We have developed a dual-catalyst aftertreatment system which utilizes the hydrocarbons present in the exhaust streams of lean-burn engines for reducing NOxemissions. The dual-catalyst aftertreatment system is a p...
Wash-coat development for Lean-burn Engine-exhaust Aftertreatment: A Novel Way of Incorporation of Binder to Pd Supported on Sulfated Zirconia Çelik, Gökhan; Gunduz, Seval; Miller, Jeffrey T.; Tao, Franklin Feng; Edmiston, Paul L.; Ozkan, Umit S. (null; 2016-11-14) As the environmental regulations are getting more stringent, it is of great importance to develop a catalytic aftertreatment system for natural gas-fired lean-burn engines to reduce the emissions of nitrogen oxides (NOx), unburned hydrocarbons (CH4, C2H6, and C3H8) and carbon monoxide efficiently. We have developed a dual-catalyst aftertreatment system which utilizes the hydrocarbons present in the exhaust streams of lean-burn engines for reducing NOxemissions. The dual-catalyst aftertreatment system is a p...
Optimal Battery Sizing for Electric Vehicles Considering Battery Ageing Gezer, Ali; Ünver, Baki Zafer; Bostancı, Emine (2022-01-01) Due to environmental issues such as emission of carbon gases and depleting natural resources, Electric Vehicles (EVs) are attracting more attention. To make EVs viable and widespread, the batteries' high cost and performance degradation problems have to be overcome. The degradation of the battery both in terms of energy capacity and power capability is highly dependent on conditions of utilization. To understand the relationship between energy utilization and battery size, an electric vehicle model that is ...

Citation Formats

Z. Artuç, “Density functional theory investigation of noble metal reduction agents on Gamma-Al2O3 in NOx storage/reduction catalysis /,” M.S. - Master of Science, Middle East Technical University, 2011.