Experimental Study of the Catalytic Oxidation of Hydrocarbons on Unsupported and Supported Platinum and Palladium

Abstract

This thesis presents a comprehensive experimental study of the oxidation of light alkanes (methane and ethane) and alkenes (ethylene and propylene) catalysed on platinum and palladium. The study covers a wide range of parameters, such as hydrocarbon type, catalyst material, catalyst structure, preparation of the catalyst and pre-treatment, reaction temperature, reactants flow rate, residence time, the concentration of reactant mixture, and the catalyst support. The catalysts were introduced in different forms and structures, which can be helpful to (a) understand how the catalyst structure and reactor design affect the catalytic behaviour and (b) provide a broad set of experimental results that can be used in developing and validating numerical models and mechanisms. The catalysts were introduced in different forms, such as (1) unsupported catalytic wires (2) unsupported nanoparticles (3) unsupported catalytic tube (4) particles supported on cerium oxide (5) supported on catalytic aluminium oxide monolith. The gaseous products from the reactions were analysed using gas chromatography while various characterisation techniques were employed to analyse the catalytic surfaces. Such a comprehensive study fills the gap in the literature to help understand the catalytic oxidation of the tested hydrocarbons under different conditions, optimise the operation parameters for catalysts, and develop existing and new numerical models. The Pd was found to have higher activity than Pt in most tested cases. Varying the reactant mixture composition was found to play a vital role in the activity of the catalytic reactions and the extent of the hydrocarbon conversion. With the supported catalyst, the calcination and pre-treatment methods were found to be key players in identifying the activity and stability of the catalyst. A novel preparation procedure was optimised to get an active catalyst with superior stability in the long-term operation.