A series CeO_2(ZrO_2)/TiO_2 catalysts(CZT catalyst) were modified with Y~(3+) and La~(3+) using the sol-gel method. The effect of Y~(3+) and La~(3+) on catalytic performance of the CeO_2(ZrO_2)/TiO_2 during selective catalytic reduction(SCR) of NOx using NH3 was investigated. Several tests were carried out the characterize the CZT catalysts

such as the X-ray diffraction

nitrogen adsorption and desorption

temperature programmed desorption of ammonia

temperature programmed reduction of hydrogen and photoluminescence spectra. The results show that

the addition of Y~(3+) and La~(3+) inhibited the transformation of TiO_2 from amorphous phase to anatase phase. In addition

both Y~(3+) and La~(3+) ions increased the specific surface area and amount of weak acid sites in the catalysts

which was beneficial for the adsorption of reaction gas on the catalyst surface. The increase of the defects species concentration and the enhancement of oxygen storage capacity was good for catalytic activity. Therefore

the additions of Y~(3+) and La~(3+) improved the catalytic activity of the catalyst at low temperatures and broadened the active temperature window while the amount was appropriate. Under condition with GHSV of 71 400 h-1

the catalytic activity(NOx conversion rate) of the 0.2 La-CZT catalyst reached 85.1% at 200 ℃ and 96.5 % at 300 ℃(the highest).