Sökning: "platinum"

Visar resultat 1 - 5 av 262 avhandlingar innehållade ordet platinum.

  1. 1. Adsorption and bonding on platinum : influence of the surface structure and chemical composition

    Författare :Emmanuelle Janin; KTH; []
    Nyckelord :Platinum; tin; low index single crystal surfaces; adsorption;

    Sammanfattning : This thesis deals with the influence of the structure andchemical composition of platinum surfaces on the adsorption ofsome molecules. Three main lines can be distinguished : 1) thecharacterisation of clean/modified surfaces, 2) the adsorptionof some simple atoms and molecules on these surfaces andfinally 3) the adsorption of 2-butenal, a bi-functionalmolecule containing a C=C group conjugated with a C=O group. LÄS MER

  2. 2. Coke on Supported Palladium and Platinum Catalysts

    Författare :Mikael Larsson; Chalmers University of Technology; []
    Nyckelord :TPO; palladium; deactivation; coke; propane dehydrogenation; microbalance; vegetable oil hydrogenation; acetylene hydrogenation; catalysis; platinum;

    Sammanfattning : Catalyst deactivation by coke formation has been investigated in three heterogeneous catalytic processes, propane dehydrogenation, acetylene hydrogenation and hydrogenation of vegetable oil. Palladium and/or platinum supported on alumina were used as catalysts in all reactions. LÄS MER

  3. 3. Platinum Group Elements in Birds of Prey

    Författare :Kristine H. Ek; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rhodium; bird of prey; platinum; laser ablation; palladium; ICP-MS; airborne particles;

    Sammanfattning : The environmental concentrations of Pd, Pt and Rh (three of the platinum group elements, PGE) have increased since the introduction of exhaust catalysts on automobiles. A limited understanding of the environmental distribution and effects of the platinum group elements has raised concern over their potential biological availability. LÄS MER

  4. 4. In situ Studies of Platinum Catalyst Sintering

    Författare :Pooya Tabib Zadeh Adibi; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nanoparticle sintering; indirect nanoplasmonic sensing; operando spectroscopy; transmission electron microscopy; platinum; catalyst deactivation; sintering kinetics;

    Sammanfattning : The damaging effect of pollutants from combustion engine exhaust on human health and environment is well recognized. Since the 70s, the three-way catalytic converter (TWC) has substantially improved the urban air quality by simultaneous conversion of CO, NOx and unburned hydrocarbons to O2, N2 and H2O. LÄS MER

  5. 5. On the Environmental Relevance of Platinum Group Elements

    Författare :Sebastien Rauch; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; platinum; ICP-MS; automobile emission; catalyst ageing; palladium; laser ablation; urban particles; bioaccumulation; rhodium;

    Sammanfattning : It has recently been demonstrated that platinum group elements (PGE) are released from automobile catalysts into the environment, raising concern over ecological and human health risks. However, there is still a lack of knowledge regarding the dispersion and transformation of PGE in the environment and it is therefore difficult to assess potential risks. LÄS MER