Příprava monolitického katalyzátoru na bázi TiO2 a CeO2 krystalizací v podkritické vodě

Abstract

This bachelor thesis deals with the preparation of TiO2-CeO2 layer/s with a molar composition of Ti:Ce = 0.9:0.1 deposited on VUKOPOR®A ceramic foam (LANIK, s.r.o.) using the sol-gel method and subcritical water processing, followed by physico-chemical characterization using nitrogen physisorption at 77 K, phase carbon determination and scanning electron microscopy with energy dispersive X-ray spectroscopy. The work consists of a theoretical and experimental part, results with discussion and conclusions. The theoretical work describes the properties and use of TiO2 and CeO2, the properties and behavior of supercritical fluids and subcritical water, and individual characterization methods of ceramic foams. Literature survey on the given topic is also a valuable part of the theoretical part of bachelor thesis. It was found out that temperature significantly affects the porosity of pure VUKOPOR®A ceramic foams in contrast to pressure, which has no effect. At a temperature of 200 °C and a pressure of 10 and 30 MPa, during processing with subcritical water, part of the Al3+ leaches out of the VUKOPOR®A ceramic foam as a result of which the macroporosity of the ceramic foams is formed and their specific surface area increases to 1.1 m2·g-1. During the subcritical water processing of TiO2-CeO2@VUKOPOR®A foams a part of the TiO2-CeO2 catalyst layer is washed away and the complete removal of organic carbon from the catalyst layer/s is not achieved. However, the catalyst layer is highly porous and possesses the specific surface area of ~22-25 m2·g-1. A good reproducibility of the preparation of TiO2-CeO2 layers on VUKOPOR®A ceramic foam was achieved. The different size of the glass balls used in the high-pressure cell for subcritical water processing of TiO2-CeO2@VUKOPOR®A foams did not affect the final properties of the catalyst layer.