Sökning: "Pt Rh"

Visar resultat 1 - 5 av 20 avhandlingar innehållade orden Pt Rh.

  1. 1. Development and Assessment of Regeneration Methods for Commercial Automotive Three-Way Catalysts

    Författare :Henrik Birgersson; Magali Boutonnet; Jim A. Andersson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; automotive catalyst; TWC; aging; sintering; Pd Rh; Pt Rh; regeneration; oxy-chlorination; dispersion; acid-leaching; mathematical modeling; reaction kinetics; Chemical engineering; Kemiteknik;

    Sammanfattning : Car exhaust catalysts were introduced in the early 1980’s, to limit the release of pollutants such as hydrocarbons, carbon monoxide and nitrogen oxides. These catalysts contain noble metals such as palladium (Pd), platinum (Pt) and rhodium (Rh) and are able to simultaneously abate all three of the above-mentioned pollutants, hence the name three-way catalyst (TWC). LÄS MER

  3. 2. Rhodium diesel-reforming catalysts for fuel cell applications

    Författare :Xanthias Karatzas; Lars J. Pettersson; James Spivey; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Autothermal reforming; auxiliary power unit; BET; chemisorption; diesel; fuel cell; hydrogen; monolith; reforming catalyst; reformer design; Rh; RhPt alloy; TEM; TPO; TPR; XRD; XPS; zone coating; Chemical engineering; Kemiteknik;

    Sammanfattning : Heavy-duty diesel truck engines are routinely idled at standstill to provide cab heating or air conditioning, and in addition to supply electricity to comfort units such as radio and TV. Idling is an inefficient and unfavorable process resulting in increased fuel consumption, increased emissions, shortened engine life, impaired driver rest and health, and elevated noise. LÄS MER

  4. 3. Studies of NOx Storage Catalysts - Preparation, Characterization, Sulfur Deactivation and Micro Kinetic Modelling

    Författare :JAZAER DAWODY; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; kinetic modelling; metal oxide additives; NO oxidation; Zeta potential; FTIR; SO2 oxidation; Al2O3; NOx storage and reduction catalysts; TEM; BaCO3; SEM; Pt precursors; sulfur deactivation;

    Sammanfattning : For the protection of the global environment, it is essential to decrease the emissions of CO2 which is a green house gas. Lean-burn and diesel engines offer relatively low CO2 emissions and good fuel economy. LÄS MER

  5. 4. Studies on Lean NOx Reduction with Ammonia. Catalysts and Sensors

    Författare :Mikaela Wallin; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; catalysis; Pt SiO2; NOx reduction; gas sensor; DFT; SCR; H-ZSM-5; in situ FTIR; LCAO; DRIFT; high throughput screening; transient ammonia supply; ammonia; microemulsion; perovskite;

    Sammanfattning : Selective catalytic reduction of NOx with ammonia, NH3-SCR, is a promising technique to reduce NOx under lean conditions, e.g. in diesel engine exhausts. The main objective of this thesis was to gain further understanding of key parameters affecting the performance of catalysts and sensors for NH3-SCR. LÄS MER

  7. 5. Oxidation of some Late Transition Metal Surfaces: Structural Studies from UHV to Atmospheric Pressure

    Författare :Johan Gustafson; Synkrotronljusfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Kondenserade materiens egenskaper:struktur; phase equilibria; crystallography; thermal and mechanical properties; Condensed matter:stucture; density functional theory; scanning tunneling microscopy; surface x-ray diffraction; high resolution core level spectroscopy; low energy electron diffraction; metal surfaces; oxidation; catalysis; egenskaper termiska och mekaniska ; kristallografi; fasjämvikt;

    Sammanfattning : The oxidation of Rh, Pd and Pt is studied under conditions ranging from ultra high vacuum to ambient pressures, with emphasis on a complete understanding of the geometry of the various oxide structures found. The investigations use a combination of various experimental methods, including high resolution core level spectroscopy, low energy electron diffraction, surface x-ray diffraction and scanning tunneling microscopy, as well as density functional theory calculations. LÄS MER