Synthesis of Improved Catalytic Materials for High-Temperature Water-gas Shift Reaction

In this investigation, we report the preparation and characterization of Co-, Cu- and Mn-substituted iron oxide catalytic materials supported on activated carbon. Co-precipitation method and low temperature treatment were used for their synthesis. The influence of chemical composition, stoichiometry, particle size and dispersity on their catalytic activity was studied. Samples were characterized in all stages of their co-precipitation, heating and spend samples after catalytic tests. The obtained results from room and low temperature Mössbauer spectroscopy were combined with analysis of powder X-ray diffraction patterns (XRD). They revealed the preparation of nano-sized iron oxide materials supported on activated carbon. Relaxation phenomena were registered also for the supported phases. The catalytic performance in the water-gas shift reaction was studied. The activity order was as follows: Cu0.5Fe2.5O4 > Co0.5Fe2.5O4 > Mn0.5Fe2.5O4. Catalytic tests demonstrated very promising results and potential application of studied samples due to their cost-effective composition

Treatment of Biogenic Iron-Containing Materials

Biogenic iron oxides could find application in catalysis but their structure and composition should be well characterized. The content of organic rests due to their origin should also be controlled. Samples of natural biomass and biomass obtained after cultivation in Adler’s medium of the Sphaerotilus-Leptothrix group of bacteria were treated by different techniques to reduce or totally remove the organic residues. The aim of the study was to find procedures, which prevent changes in the oxidation state of the iron and of the type of iron-containing compound(s) during treatment. Mössbauer spectroscopy, IRS, DTA, and SEM were used in the study. Chemical treatment with H2O2 or NaOH at room temperature did not significantly change the samples. Thermal treatment in oxidative flow mixture conducted up to 250 °C resulted in a transformation of the iron-containing phases only. The organic matter, which is included in the structure of the particles, cannot easily be affected. DTA revealed that removal of organic rests occurred in the interval of 250–600 °C. However, the transformation of the initial compounds could not be prevented using such a treatment