Nanostructured ferric oxides and sulfated ferric oxides are of high interest in catalysis, e.g. for hydrocarbon isomerization. Sulfated ferric oxides are often prepared by immersion of ferric oxides in sulfate containing solutions which technique is facile to conduct, yet poorly reproducible. This problem is circumvented by sulfate incorporation into ferric oxide particles during precipitation. This way of intrinsic sulfation generated ferric oxides with defined properties. The precipitation reaction is accomplished by using a microjet mixer, in which ferric sulfate is brought to reaction with ammonia, what allows for forming schwertmannite and ferrihydrite qualities with defined sulfate content. As ferric oxide synthesis is conducted at ambient conditions, while catalysis mainly occurs at elevated temperatures, it is important to study structural as well as chemical changes during heating. Thus these materials were analysed in terms of structural and chemical changes during heating. In this course it was found that both materials are transformed into hematite, the crystallization degree as well as specific surface properties of which depend both on annealing temperature and the precursor used. This transformation was accompanied by dehydration and liberation of sulfur trioxide.

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Sulphuric acid is the chemical with highest production rates in the world. At present, it is mainly synthesized using vanadium pentoxide as catalyst, which determines the applied production process particularly in terms of gas pre‐treatment and heat management. For processes, which cannot be run with vanadium pentoxide, alternative catalysts are required to make different SO2 qualities accessible to sulphuric acid production. Ferric oxides are a very promising alternative, since they combine higher thermal with improved chemical stability. Within this study, various ferric oxides were examined with regard to conversion rates and structural changes during application. Effects of crystal structure, particle size as well as thermal treatment and the influence of precipitation conditions were studied. Although conversion rates are very promising, it has become apparent, though, that these materials cannot compete with vanadium pentoxide in terms of conversion rate as well as long‐time stability, yet. Nevertheless, from the results of this study, it is clear that high potential lies in focused catalyst optimisation.