Highly selective and stable propane dehydrogenation to propene over dispersed VO_x-species under oxygen-free and oxygen-lean conditions

For the first time, we reported on a highly selective propane dehydrogenation to propene over SiO2- supported dispersed VOx species under oxygen-free and oxygen-lean conditions. Propene selectivity above 80% was achieved with propane conversions above 45% at 823–843 K. At operation under oxygenlean conditions, consecutive propene conversion to COx was significantly suppressed and propene was formed additionally via the highly selective non-oxidative dehydrogenation route over the same catalyst. Usage of SiO2 supports (MCM-41, SBA-15, SiO2) with no strong acid sites and co-feeding of small O2 amounts lead to very limited coke formation (<2 wt. % after 20 h on-stream operation). This results in only slight decrease in time-on-stream performance (ca. 10% of deactivation during 20 h)

Preparation and characterisation of single phase (MoVW)₅O₁₄-type catalyst material

MoVW based materials are highly effective catalysts for partial oxidation reactions such as conversion of acrolein to acrylic acid. They offer a high selectivity, high yields and a good long term stability. Preceding work has identified the catalytically active phase of the MoVW catalyst and characterised it by Raman spectroscopy. The current work has been carried out to synthesise and characterise this active (MoVW)5O14 type structure

On the formation and decomposition of active phases in Mo₉V₃W_1.2O_x catalysts during operation in the acrolein oxidation to acrylic acid

The activation process of Mo9V3W1.2Ox mixed oxide catalysts in the reaction of acrolein oxidation to acrylic acid was investigated for various reaction conditions. Changes induced in the catalytic performance by these different activation procedures could be correlated to structural changes of the MoVW mixed oxide catalyst, as proven by XRD and electron microscopies (SEM, TEM, and EDX)