Visar resultat 1 - 5 av 286 avhandlingar innehållade ordet platinum.
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
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
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
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
Sammanfattning : Pt is one of the most commonly used catalysts for green energy applications, such as fuel cells, electrolyzers, and dye-sensitized solar cells. Although enormous effort has been put into improving the catalytic activity and minimizing the usage of Pt in the catalysts, the low abundance and high price of Pt still limit the large-scale commercialization of green energy devices and facilities. LÄS MER