Effective processes of phenol degradation on Fe3O4–TiO2 nanostructured magnetic photocatalyst

The photocatalytic activity of nanocrystalline titanium dioxide containing various phases (anatase, rutile) can be used for example for the splitting of water into H2 and O2 under ultraviolet light. In our study the suitability of magnetic Fe3O4–TiO2 nanostructures obtained by microwave-assisted solvothermal method was checked for degradation of phenol. The selected method for the synthesis of Fe3O4–TiO2 does not require the calcination process and could be effective below 170 °C. The average size of the crystallites of Fe3O4 was determined to be ~27 nm, while that of surrounding TiO2 particles equals to about 17 nm. High photoactivity in the phenol degradation process was confirmed for synthesized nanomaterials. Their activity can be controlled by the TiO2:Fe3O4 mass ratio. After 180 min of the reaction, the conversion of phenol was 100% over the commercial catalyst (P25) and 70% over the Fe3O4–TiO2(3 ml TBOT). Superparamagnetic behavior of the obtained nanostructures was evidenced with the finite size effects and superexchange interactions playing prominent role. Magnetic properties and chemical stability permitted easy separation of the obtained nanostructures from the solution after the photocatalytic degradation process and their re-use.