Researchers have discovered that sodium modification of ceria leads to boost in ceria catalytic activity for the formation of hydrogen from an alcohol that can be derived from renewable resources, isopropanol. Infiltrating sodium carbonates into ceria disrupts its structure resulting in an increase in the number of surface oxygen vacancies. This was shown using a combination of Raman spectroscopy, temperature programmed reactions spectroscopy, and chemisorption methods. The distribution of sodium within the solid was investigated using 23Na solid-state nuclear magnetic resonance and by X-ray photoelectron spectroscopy. After depositing palladium onto the sodium-ceria material, the catalyst was used to hydrogenate phenol (a compound that can be obtained from biomass) into KA oil (a commercial precursor for nylon). Pd/Ce-Na showed a six-fold increase in transfer hydrogenation activity over Pd/CeO2. The entire process was run continuously in a flowing stream of water and alcohol, showing that efficient production of industrially relevant chemicals can be achieved in an environmental friendly way. The enhancement of adsorption and redox active sites on ceria through this simple sodium modification approach is expected to be broadly applicable to other ceria-based catalysis.
Temperature programmed surface reaction profiles of 2-propanol on CeO2 and Ce-Na for m/z=58.
Transfer Hydrogenation over Sodium-Modified Ceria: Enrichment of Redox Sites Active for Alcohol Dehydrogenation