Ethylene Oxidation on Polycrystalline Platinum over Eight Orders of Magnitude in Ethylene Pressure: A Kinetic Study in the Viscous Pressure Regime

摘要: Abstract C 2 H 4 oxidation on polycrystalline Pt films and foils at T  = 373–473 K was studied with mass spectrometry in the pressure ranges 10 −6 –10 Torr 0.3–1500 O (1 Torr = 133.3 Pa). A new, “spatially resolved gas sampling” method enabled true kinetic data to be collected viscous regime. In situ measurements of surface hydrogen a capacitance–voltage technique ex characterization Auger electron spectroscopy atomic force microscopy were also performed. No structure sensitivity respect sample grain size could seen. The reaction orders +1 −1 oxygen excess, −2 +3 weak ethylene −0.5 large respectively. apparent activation energy between 30 75 kJ/mol for different reactant mixtures. rate qualitatively fitted simple Langmuir–Hinshelwood scheme excess regimes, assuming competitive adsorption , abundant molecular desorption reactant, strong self-inhibition adsorption.