On the basis of our previous work, we developed a new type of catalyst (e.g. photocatalysts) to degradate nitrogen oxides (NOx) Recently, a series of photocatalysts Such as strontium titanate (SrTiO3) were prepared by sol-gel method, their photocatalytic activities of NO degradation were also studied. The obtained samples were characterized by differential thermal analysis and thermal gravimetric analysis, X-ray diffraction and transmission electron microscopy. The as-prepared photocatalysts have a perfect perovskite structure, and pure samples can be obtained when the corresponding sol-gel precursors were calcined at 600 degrees C in muffle. With the temperature increasing, the grain size of SrTiO3 samples grew large steadily and the crystallinity became better. The optimal synthesis of SrTiO3 was determined to be 700 degrees C calcination. Our current experiments indicated that some parameters such as lamp-house, calcinations temperature had a strong effect on the designed photoreaction, the concentration of nitric oxide at 716 mg/m(3), the degradation rate of nitric oxide can increase above 92%. (C) 2008 Elsevier B.V. All rights reserved.