Abstract: SnO2@TiO2 coated particles have been prepared with Ti(OC4H9)4 and SnO2•nH2O as precursors by coated on active surface.In order to improve the photocatalytic degradation activity of SnO2@TiO2 for DDVP,the conditions of preparation were studied and better photocatalytic activity was obtained.Its morphology and structure were characterized by XRD,SEM,TEM,XPS、IR and BET.The result indicated:That SnO2@TiO2 is composed of nanometer ranatase TiO2 and rutile SnO2,and the photocatalytic activities of SnO2@TiO2 are better than those of SnO2 and TiO2,the apparent rate constant k of the photocatalytic degradation of DDVP is related to the initial concentration of DDVP solution.The reaction is not a simple zeroorder reaction.

Key words: Sol-precipitation method, Nanometer, SnO₂@TiO₂, Photocatalytic degradation, DDVP