Synergistic Effect of Noble Metal Dispersion and Metal-Support Interactions in Anion-Exchanged Layered Metal Hydroxides for Efficient CO2 Hydrogenation Catalysis

This project aims to explore the use of noble metal-based catalysts for the CO2 hydrogenation reaction with the goal of producing liquid fuels, specifically methanol. The CO2 molecule is difficult to activate due to its thermodynamic stability and kinetic inertness, making the conversion kinetically limited. The conventional Cu/ZnO catalyst systems, while widely used, have limitations in terms of low-temperature activity, the formation of by-products, and oxidation of active phases during the reaction course. Noble metal-based catalysts have the potential to overcome the CO2 activation energy barrier at low temperatures and milder pressures, but they typically have low activity and sintering issues, as well as high cost. The project will focus on improving noble metal dispersion and interactions with the metal oxide support, to increase activity, selectivity, and stability. The hydrotalcite phase will be used as a precursor for catalyst formation, with the following objectives: cation coprecipitation to adjust the elemental composition of the hydrotalcite phase, anion exchange of carboxylates with noble metal-ligand complexes, thermal treatment of the hydrotalcite precursor to form the mixed metal oxide support and reduce noble metal complexes, and on-stream evaluation of catalyst activity and stability. The prepared catalysts will be evaluated in a conventional high-pressure fixed-bed reactor under varying conditions of temperature (140 to 300°C) and pressure (1 to 50 bar). The best-performing catalyst will undergo long-term stability testing and investigation of noble metal migration and agglomeration. The reaction pathways will be investigated using in situ and operando testing of catalysts with different metal oxide supports. The results of this project will contribute to the development of efficient and stable noble metal-based catalysts for CO2-to-methanol hydrogenation, offering a promising alternative to conventional Cu/ZnO catalysts for the production of liquid fuels from CO2.