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|1. (WO2017200406) METHOD OF PREPARATION OF METAL OXIDE CATALYST|
|Applicants:||POLITECHNIKA KRAKOWSKA IM. TADEUSZA KOŚCIUSZKI
|Title:||METHOD OF PREPARATION OF METAL OXIDE CATALYST|
A method of preparation of metal oxide catalyst comprising preparation of a suspension of nanoparticles of an active-phase precursor using an ultrasonic field, supporting and immobilizing the nanoparticles of the precursor onto a carrier, drying and calcinating the carrier with the active-phase precursor immobilized thereon is characterized in that in the first step of the method a deoxygenated reaction solution containing salts of chromium (III) dissolved in water is treated with ultrasonic waves having power of 70 to 100 W, frequency of 20 kHz, an amplitude of 60 to 100% at a temperature of from 10 °C to 60 °C for 15 up to 60 minutes and during the sonication process the solution is subjected to discrete treatment of ultrasounds in intervals lasting 2 to 5 minutes, and downtimes between them last 20 to 50%, preferably 30 to 40% of the time of the treatment. In addition, an alcohol having carbon atoms of 1 to 4, preferably ethanol, is added to the solution in such amount that the concentration of said alcohol is between 1 and 3% by volume and said alcohol is added to the solution, at the latest, during the sonication process. The nanosuspension, which is the result of the ultrasonic waves acting and which contains Cr3+ and Cr2+ ions and metallic forms of chromium, is supported onto the carrier.