表面活性剂对光催化还原法合成纳米Ag/TiO_2影响的电镜观察

TEM studying the effects of the surfactant on the nanometer silver cluster formation on TiO_2 via photocatalytic reduction

在透射电子显微镜下 ,通过对加入表面活性剂修饰纳米TiO2 粒子前后以及在不同溶胶稳定态下光催化还原合成金属纳米银簇的观察发现 :适量的表面活性剂能有效改善纳米TiO2 在水中的分散度 ,提高颗粒的稳定性 ,过量的表面活性剂将导致胶束的形成 ;在稳定的溶胶状态下 ,金属纳米银簇能稳定负载在纳米TiO2 上 。

TEM was used to observe the difference of the TiO 2 particles before and after ion surfactant modification, and to observe the silver morphology loaded on the TiO 2 particles via photocatalytic reduction in different colloid condition. It was found that the appropriate quantity of ion surfactant (concentration lower than the critical micelle concentration (CMC)) could improve the dispersion and the stability of the nanometer TiO 2 particles in water solution. At concentration higher than the CMC value, the surfactant led to the formation of agglomeration of the particles. Furthermore, silver clusters could be produced in the stable and dispersive colloid condition. No formation of silver cluster was observed in the unstable or agglomerative conditions. TEM provided forceful and illustrative evidence during the experiments.