A novel, hierarchically developed surface kinetics for oxidation and reforming of methane and propane over Rh/Al2O3

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This thesis develops a surface reaction mechanism for the oxidation of H2 and CO, water-gas shift (WGS), reverse water-gas shift (R-WGS), and the oxidation and reforming of methane and propane over a Rh/Al2O3 catalyst. The aim is to enhance understanding of the reaction kinetics involved in synthesis gas production. A stagnation-flow reactor is constructed to study the kinetics of various gas fuels (e.g., H2, CO, CH4, C2H6, C3H8) and evaporated liquids (e.g., water, ethanol, methanol, iso-octane). This reactor configuration allows for one-dimensional modeling of coupled diffusive and convective transport, creating well-defined boundary conditions and eliminating heat and mass transport effects from the kinetic model. Boundary-layer composition profiles are measured using a micro-probe sampling technique, with gas-phase concentrations analyzed by MS and FTIR. The stagnation disk is coated with a Rh/Al2O3 catalyst via a spin-spray technique, and various microscopy methods are employed to determine the catalyst's physical properties. A new CO chemisorption TPD technique measures the catalytically active surface area. The study examines multiple reaction paths for methane and propane oxidation and reforming under varying conditions, focusing on heterogeneous reactions while neglecting gas-phase reactions. Numerical simulations support the development of an elementary-step-like surface reaction mechanism, ensuring thermodynamic con