The adsorption and photochemical reduction process of Cu! at the surface of nanocrystalline TiO2 was investigated using in situ quartz crystal microbalance(QCM). It was found that the adsorption of Cu! onto active sites of nanocrystalline fit the pseudo-second-order reaction better than the pseudo-first-order reaction, and that the rate constant of the reaction was estimated to be about 0.09 g·mmol-·1min-1. In addition, it was also found that the adsorption amount of Cu! at the surface of TiO2 was affected by pH、concentration and coexisting an- ions, and the saturated amount of adsorbed Cu! was approximately 1.5 mmol·g-1 at pH 4. During UV illumina- tion, the frequency of QCM decreased gradually, which meant the photoreduction deposition of Cu! from the solution, moreover, the rate of photodeposition of Cu! increased with increasing pH of solution, and the rate of photoreduction enhanced obviously when the organics were introduced.
