The active phase of Pt(110) during catalytic CO oxidation

Abstract: CO oxidation is an important topic in heterogeneous catalysis, due to its role in industrial processes such as pollution reduction in the auto industry, and ethanol or other fuel production. In the automotive catalytic converters CO oxidation reduces the poisonous CO to CO2 by reacting with O2. Oxidation catalysts such as Pt, Pd and Rh are frequently used as catalytic converters for CO oxidation in cars. These metals are called model catalysts, and catalytic CO oxidation over these metals is one of the most widely studied reactions in the eld of surface science. Despite of extensive research, the phase responsible for the catalytic activity is still under debate. Traditionally, such studies were done under simplied conditions, in Ultra High Vacuum (UHV). However, in real industrial operations, heterogeneous catalysts are exposed to harsh environments. This thesis reports on the active phase of Pt(110) during catalytic CO oxidation, at pressures up to 510 mbar and temperatures up to 625 K. The surface structure is studied using in situ Surface X-ray diraction, and to study the catalytic reaction, the gas phase in the vicinity of the surface is studied using Mass spectroscopy. It was found that Pt surface oxide structures are at least as active toward CO oxidation as the metallic surface. Apart from addressing the burning question on the active phase of Pt for CO oxidation, this knowledge will help to further solve the existing problems of CO oxidation catalysts, such as oxygen poisoning. The knowledge gained can further contribute to future development of novel heterogeneous catalysts with enhanced activity, selectivity, and improved lifetime.