Combined quantitative FTIR and online GC study of Fischer-Tropsch catalysts

Abstract A method for the quantification of the chain length of surface hydrocarbon species on Fischer-Tropsch catalysts by in-situ FTIR was combined with online gas chromatography in order to investigate any potential relationship between adsorbed hydrocarbons species and those detected as reaction products. By varying the reaction conditions and the active metal, changes to the chain lengths of surface species and the product distribution were monitored. Results show that the species observed spectroscopically are predominantly adsorbed reaction products which do not directly relate to the detected reaction products. Hydrocarbon species which can be transported to the support material (γ-alumina) may be ascribed to oxygenated products which are not produced in detectable amounts by GC at low conversion but are selectively adsorbed from the gas phase.