Preparation And Photocatalysis Properties Of Nano-powder TiO₂and Rare Earth Praseodymium Ion Doped TiO₂by Activated Carbon Absorption

TiO₂with the advantage of low cost, better stability and good photocatalyticefficiency, is considered to be the most prospective photocatalyst. However, both thetransition from anatase phase to rutile phase and the agglomeration in calcining progresscan affect the photocatalytic activity of TiO₂. To solve these problems, researchers haveimproved the structure of photocatalyst and the photocatalytic efficiency in the way ofadding extra reagent and regulating hydrolysis condition in the conventional methods likesol-gel, microemulsion, hydrolysis and precipitation.Anatase TiO₂nano-powders and Pr³⁺/TiO₂nano-powders, the mole fraction of Pr³⁺is0.07%, were synthesized by hydrothermal synthesis with tetraisopropyl titanate onactivated carbon and caclined at400℃,500℃,600℃,700℃,800℃, respectively. Theobtained materials were characterized by thermo gravimetric-differential thermalanalysis（TG-DTA）, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, BETand ultraviolet-visible absorption spectrometry（UV-Vis）, respectively.Activated carbon acted as a barrier which prevents the powders agglomeration duringthe calcining progress. The results showed that TiO₂nanopowders calcined at600℃hadan optimal dispersion behavior and single anatase phase. The particle size was about18nmand the surface area was about70m²/g.In the condition of the photocatalytic rates of P-25, the obtained TiO₂nanopowdersand Pr³⁺/TiO₂were78%,96.7%,98.3%respectively. Doping praseodymium (Pr³⁺) raisedthe photocatalytic activity of TiO₂powders.