Stability of TiO2 forms (anatase–rutile) in the Y2O3?Ti(OBu)4?Rb2CO3 system prepared by sol–gel process

Three different sol–gel routes were used in order to study the stability and the crystallinity of the ternary system Y₂O₃, Ti(OBu)₄, Rb₂CO₃. Different techniques such as FTIR, ¹³C NMR TGA, DTA and XRD were used to characterize xerogels and final products. Results demonstrated that using hexanoic acid during the sol step preparation influences structural changes in the precursor gel. The effect of heat treatment to eliminate the organic material from xerogels was investigated by thermal gravimetry and differential thermalanalysis. According to the ratio of acetic acid to hexanoic acid, the phase structure of TiO₂, viz. anatase to rutile phase, could tailored. The photocatalytic activity of the prepared catalysts, under sunlight irradiation, was evaluated using 2‐naphthol as a pollutant model. Results showed a great enhancement in the photocatalytic efficiency for doped TiO₂ sample prepared in the presence of 30acet–70hex. Copyright © 2010 John Wiley & Sons, Ltd.