Study on photocatalytic oxidation of nitrite over RE/TiO2 photocatalysts

RE/TiO2 photocatalysts were prepared by using sol-gel method with rare eart h (RE = La, Ce, Er, Pr, Gd, Nd, Sm) salts and titanium tetrabutoxide as pre cursors, and were characterized by XRD, IR, UV-Vis diffuse reflection techn iques. The photocatalytic activity of the catalysts was tested with nitrite as objective decomposition substance. As a result, doping suitable content of rare earth elements can efficiently expand the range of light absorbed by the catalysts. At the same time, the doping can be beneficial to NO2- ad sorption over the catalysts. Doping RE in TiO2 can, more or less, enhance t he photocatalytic activity. Gd/TiO2 shows the highest catalytic activity am ong all the RE/TiO2 samples concerned. The doped RE content is an important factor for the photocatalytic activity; the optimum RE content is about 0. 5%.