Effect of Doping with Alumina on the Microstructure and Photo-catalytic Activity of Nanosized TiO_2 in Rutile Phase

The nanosized TiO2 in the rutile phase was doped with alumina to suppress its photo-catalytic activity. The obtained samples were characterized by XRD, XPS, TEM and BET techniques. The results show that the optimal calcination temperature is 800 ℃, and the optimal Al2O3 concentration is m(Al2O3):m(TiO2)=1:5. The growth of crystalline size and particle size is suppressed from adulteration. With the increase of m(Al2O3):m(TiO2), the crystalline size and particle size of nanosized TiO2 decrease progressively, at the same time, the BET surface area and pore volume of nanosized TiO2 increase. According to the difference of electron binding energy and the variety of unit cell parameters, it can be inferred that the lattice of nanosized TiO2 is doped with Al3+. The saturated concentration of dopant is m(Al2O3): m(TiO2)=1:20. When m(Al2O3):m(TiO2)≥1:10, the crystal structure of alumina appears.