The central idea of the project was to prepare highly active catalysts for production of alkenes from alkanes, simultaneously utilizing CO2 as a mild oxidant. Our preliminary research showed that several catalysts displayed high selectivity in the oxidative dehydrogenation of propane to propene. The promising candidates were then chosen for further investigation. With the ERC grant we took the research to the next stage and accomplished several tasks. First of all, we were able to fully characterize chosen materials (Pd/CeZrAlOx and Pd/CeO2) using several techniques (e.g. High-Resolution Transmission Electron Microscopy (HR-TEM), Temporal Analysis of Products (TAP), and Extended X-ray Absorption Fine Structure (EXAFS). Such characterization helped us to understand the correlation between catalyst high selectivity and structure. In addition, we examined the effects of reaction temperature, reactant stoichiometry, and the presence of diluents in the CO2 stream. We therefore optimized the catalytic reaction. Kinetic investigations were also performed to establish the rate expression that will inform the reaction engineering during potential scale-up. Deactivation of the material and catalyst lifetime were studied to ensure the material will be stable under operation conditions. All these data are now included in the draft of the publication which we submitted to Nature Catalysis.
From the very beginning it was clear that the socio-economic impact of this project will be high. The process, where in one step alkenes are formed and CO2 is utilized under atmospheric pressure, offers environmental and economic benefits. It utilizes one of the main greenhouse gases, CO2 and leads to production of the 2nd most demanded olefin in industry, propene. It is noteworthy, that only CO and H2O are formed as by-products. Furthermore, separation of these by-products from the hydrocarbon stream is relatively simple, and CO formed in this reaction can further be applied in processes such as Fischer-Tropsch, synthesis of methanol or the production of H2 in the water-gas shift reaction. Further consideration could be given to the use of an OXO process to prepare butanol or 2-ethylhexanol.
