胶体半导体表面光还原反应动力学的ESR研究──I．ZnS、CdS光还原效率的ESR研究

ESR STUDY OF PHOTOREDUCTION KINETICS ON THE SURFACE OF COLLOIDAL SEMICONDUCTOR──Ⅰ.ESR STUDY OF PHOTOREDUCTION EFFICIENCY OF ZnS AND CdS

用电子自旋共振（ＥＳＲ）法以４－氧－２，２，６，６－四甲基－哌啶酮（４－ｏｘｏ－ＴＥＭＰＯ）作为电子受体，研究了ＺｎＳ和ＣｄＳ胶体表面光还原效率的差异，发现在本实验体系中胶体表面光还原对于底物是零级反应，其原因可能是由于胶体的吸附作用使得４－ｏｘｏ－ＴＥＭＰＯ在胶体表面处于饱和状态。测得的反应动力学常数能够定量地表示胶体半导体光还原效率的差异。实验结果表明，由于吸收光谱范围的限制，ＺｎＳ胶体在不同波长光照下以及ＺｎＳ和ＣｄＳ胶体在同样光照下的光还原效率均不相同。

Using 4-oxo-TEMPO as electron acceptor, the difference of photoreduction efficiency of ZnS and CdS was investigated by ESR method. The photoreduction reaction on the colloid surface was zero-order for reduction substrate.The reason may be the adsorption effect of colloid,which causes 4-oxo-TEMPO saturated on the surface of colloid.Kinetics constants measured can quantitatively express the photoreduction efficiency difference of colloidal semiconductors.Because of the restriction of absorption spectra, the photoreduction efficiency of ZnS under difference wavelength irradiation and ZnS, CdS under the same irradiation all are different.