The Evaluation of Oxide Catalysts’ Properties in Test Reactions

Abstract

Oxidative dehydrogenation of cyclohexane could be very promising and complementary test reaction to evaluation of redox properties of the catalyst surface, which are very important in the selection of materials for neutralisation of NO x . The process is autothermic and it runs in significantly lower temperatures than conventional dehydrogenation.

Structure Sensitivity of Oxidative Dehydrogenation of Cyclohexane over FeOx and Au/Fe3O4 Nanocrystals

“…However, if the rates are normalized with the surface area (Tables and ), they are higher (by ∼50%) for the octahedral catalysts than the cubes. The rates for the FeO x and Au/FeO x samples studied in this work are higher than those for the NiFe 2 O 4 catalysts reported by Turek et al, but are lower than the AuPd–TiO 2 catalyst studied by the Hutchings group, as shown in Figure . The rates are also comparable to those reported for 12 nm Co 3 O 4 nanocubes in the same gas composition as what is used here .…”

“…For all samples studied, the dehydrogenation products started to appear above 200 °C. This temperature is typical for activation under oxidative conditions, , but it is low compared with the corresponding anaerobic processes. Both cyclohexene and benzene are formed over the iron oxide nanoshapes, but benzene is the only dehydrogenation product in the presence of gold.…”

Oxidative Dehydrogenation of Cyclohexane on Cobalt Oxide (Co3O4) Nanoparticles: The Effect of Particle Size on Activity and Selectivity

“…The selective dehydrogenation of cyclohexane to cyclohexene, for example, is a key step in the production of adipic acid that is used in the production of nylon. Oxygen is often used as coreagent to enhance dehydrogenation as it lowers the temperature of activation and inhibits coke formation and can provide for direct oxygen functionalization. − Great care must be taken in such oxidative dehydrogenation and functionalization processes to minimize the overoxidation to CO 2 …”

“…Much of the reported literature on the dehydrogenation of cyclohexane is focused on the use of supported transition metal particles , whereas the oxidative dehydrogenation of cyclohexane is more typically carried out on oxides. − Earth abundant metal oxides would be significantly cheaper and provide a more viable alternative especially in the conversion of fuels. More recent studies suggest that nanometer-sized cobalt oxide particles are highly active for carrying out CO oxidation and may be quite active for the oxidative dehydrogenation (ODH) of alkanes.…”

Pentane, Hexane, Cyclopentane, Cyclohexane, 1-Hexene, 1-Pentene,cis-2-Pentene, Cyclohexene, and Cyclopentene at Vapor/α-Alumina and Liquid/α-Alumina Interfaces Studied by Broadband Sum Frequency Generation

“…Because molecular structure and orientation play crucial roles in interfacial chemistry, the interactions of organic molecules with surfaces can depend heavily on the nature of the hydrocarbons involved, thus posing a difficulty in many areas of science and technology. For instance, cyclic alkanes are often used to screen potential oxidative dehydration catalysts, but the results are often interpreted to be general for alkanes. − Likewise, the atmospheric chemistry of biogenic emissions with oxide dust aerosols, which are of great relevance to climate change, ,− involves cyclic, bicyclic and acyclic structures. − Yet, most model systems do not address chemical diversity in their studies. Thus, there is a need to understand the similarities and differences between the interactions of linear versus cyclic hydrocarbons at oxide interfaces.…”