Preparation of nanostructured metal oxides by using extraction techniques belongs to unconventional preparation routes. Using assets of supercritical and pressurized fluids the metal oxides possessing significantly improved textural and structural properties can be synthesized than using conventional calcination. The project deals with investigation of preparation of various macroscopic forms (powders, thin films, monoliths) of nanostructured materials based on TiO2, CeO2, ZrO2 and ZnO using sol-gel processes, thermal hydrolysis and extraction techniques developed for purpose of oxides purification and direct crystallization. Besides extraction by pressurized water and/or by super/subcritical methanol, also extraction by supercritical carbon dioxide with modifier/s will be tested and optimized in a broad range of experimental conditions. The influence of individual types of extraction approaches and experimental conditions on microstructure will be examined. Extracted metal oxides will be compared with calcined analouges. Their photocatalytic activity and toxicity will be assessed.