纳米半导体表面光诱导电子传递动力学——以4oxoTEMPO为电子受体TiO_2表面光还原效率的ESR研究

TRANSFERRING KINETICS OF LIGHT INDUCED ELECTRON ON THE SURFACE OF NANOMETER SEMICONDUCTORS——ESR Study of Photoreduction Efficiency of TiO\-2 Nanometer Semiconductors Using 4 oxo TEMPO as Electron Acceptor

以４氧２ ，２ ，６ ，６四甲基哌啶酮（４ｏｘｏ２ ，２ ，６ ，６ ，ｔｅｔｒａｍｅｔｈｙｌ１ｐｉｐｅｒｄｉｎｙｌｏｘｙ 简称４ｏｘｏＴＥＭＰＯ） 作为电子受体，利用消自旋（Ｓｐｉｎ ｃｏｕｎｔｅｒａｃｔｉｏｎ） 的ＥＳＲ 方法，定量研究了ＴｉＯ２ 纳米半导体表面光诱导电子传递动力学，确定了ＴｉＯ２ 纳米半导体表面光还原速率方程和反应动力学常数．结果发现，在本实验体系中，ＴｉＯ２ 纳米半导体表面光还原对于底物是零级反应，而对于ＴｉＯ２ 则为一级反应，所测得的反应动力学常数能定量地表示ＴｉＯ２ 纳米半导体表面的光还原效率．不同波长光照及相异ｐＨ 值对ＴｉＯ２ 纳米半导体表面光还原速率有不同程度的影响．

By the use of 4 oxo 2,2,6,6 tetramethyl 1 piperdinyloxy (4 oxo TEMPO) as electron acceptor, transferring kinetics of light induced electron on the surface of TiO\-2 nanometer semiconductors was studied quantitatively by ESR spectrosocpy. It was found that the photoreduction reaction on the TiO\-2 nanometer semiconductor was zero order for the reduction substrate, and first order for TiO\-2 nanometer semiconductor. The photoreduction efficiencies of TiO\-2 nanometer semiconductors under different irradiation wavelengths and different pH are discussed. \;