A detailed study of the activity and deactivation of zeolites in hybrid Co/SiO2-zeolite Fischer–Tropsch catalysts

Towards liquid fuels from biosyngas: effect of zeolite structure in hierarchical-zeolite-supported cobalt catalysts

Wax on, wax off: Bifunctional cobalt-based catalysts on zeolite supports are applied for the valorization of biosyngas through Fischer-Tropsch chemistry. By using these catalysts, waxes can be hydrocracked to shorter-chain hydrocarbons, increasing the selectivity towards the C5 -C11 (gasoline) fraction. The zeolite topology and the amount and strength of acid sites are key parameters to maximize the performance of these bifunctional catalysts, steering Fischer-Tropsch product selectivity towards liquid hydrocarbons.

CoMOR zeolite catalyst prepared by buffered ion exchange for effective decomposition of nitrous oxide

Co contained MOR zeolite catalysts with high Co loadings were successfully synthesized by buffered ion exchange at pH 8, and were tested for N(2)O catalytic decomposition. The high exchange level of synthesized CoMOR(x)-BIE catalysts probably benefits from the maximizing hydroxycomplexes Co(OH)(+) ion in the buffered solution, which is more preferred for the ion exchange with the zeolites. It has been found that the novel CoMOR(x)-BIE catalysts exhibit excellent catalytic activities, which is attributed to the large population of isolated Co(2+) ions on ion exchange positions. The most active CoMOR(130)-BIE catalyst shows high resistance to the inhibition of oxygen, NO and water vapor. Furthermore, stability tests indicate that the CoMOR(130)-BIE catalyst has no obvious deactivation under simulated emission conditions after reaction for more than 100 h. This extraordinary durability could be related to its high Co(2+) content and low Brönsted acidity sites in the catalyst, which facilitate the stability of active isolated Co(2+) on ion exchange positions. Thus, the CoMOR(130)-BIE catalyst shows a great potential as a cost-effective catalyst for N(2)O elimination in future applications.

Future Refining Catalysis - Introduction of Biomass Feedstocks

Refining catalysis has been developing over many years to satisfy the demand for high-quality and environmentally-acceptable automotive fuels. Biomass-derived feedstocks have been recently introduced into refineries posing thus new challenges for refining processes and catalysis. The manuscript focuses on three prominent biomass-derived feedstocks: triglycerides, bio-oils and Fischer-Tropsch products from gasified biomass. Due to high oxygen content in biomass feedstocks, deoxygenation processes play an important role in upgrading of these feedstocks. Thus, first peculiarities of deoxygenation are discussed in detail in the context of hydrotreatment processes. Different possibilities of triglycerides and bio-oils deoxygenation including their coprocessing with crude-oil-derived fractions are described. Since biomass-to-liquid processes are very important for the conversion of general biomass into liquid products, the second part deals with the aspects of biomass conversion to synthesis gas, Fischer-Tropsch synthesis and introduction of new co-catalysts.