Effects of silicon doping on phase transformation mechanism of titanium dioxide

Abstract

Under the physical mixed doping of different amounts of SiO2, high temperature in-situ XRD, TEM, XPS and Rietveld full spectrum fitting were used to analyze the change rule of chemical bond and the influence of silicon on the transformation mechanism of anatase to rutile (A→R) TiO2.The results show that the influence mechanism is controlled by distortion energy and crystal nucleus formation. When the doping amount of SiO2 is less than 7.5% (mass fraction, the same as below), the phase transition is inhibited. At this point, Si4+ replaces Ti4+ ions in the titanium dioxide lattice, resulting in distortion and inhibiting the A→R transformation of titanium dioxide. When the doping amount of SiO2 is greater than 7.5%, it is the promotion effect. At this time, the excess SiO2 acts as the crystal nucleus of rutile, thus promoting the transformation of A→R.

Keywords

• doping
• titanium dioxide
• solid solution
• phase transformation
• silicon dioxide