| Since the reform and opening up, people was eager to pursue the economic development at the expense of destroying the environment. Thus, a serious of environmental problems threatening to health and development has been caused. Photocatalytic technology is a popular method to deal with the water pollution. Much attention have been paid to fabricate the semiconductor photocatalysts with suitable band gap since the past two decades. In recent years, it’s still a challenging task to explore effective and stable semiconductor photocatalysts including semiconductor-semiconductor heterojunction, semiconductor-metal heterojunction, semiconductor-carbon heterojuntion, multi-components heterojunction and so on.In this dissertation, CdS was chosen as the basic semiconductor and we designed our photocatalysts according to the semiconductor-semiconductor heterojunction and semiconductor-carbon heterojunction. We synthesized ZnxCd1-xS alloyed hollow nanospheres, carbon coated CdS nanospheres and carbon coated ZnxCd1-xS nanospheres and improved the photocatalytic effect in different degree. This paper mainly includes the following three parts:1. Facile synthesis of uniform ZnxCd1-xS alloyed hollow nanospheres for improved photocatalytic activitiesA facile template-free method has been developed for the fabrication of uniform ZnxCd1-xS (0≤x≤1) alloyed hollow nanospheres. The as-prepared ZnxCd1-xS hollow nanospheres have been investigated by X-ray power diffraction, field-emission scanning electron microscopy and transmission electron microscopy; respectively. The research results indicate that the as-prepared ZnxCd1-xS hollow nanospheres are with an average diameter of 100 nm and 30 nm in shell thickness. As expected, the as-prepared Zn0.5Cd0.5S alloyed hollow nanospheres show best photocatalytic performance towards photodegradation of Rhodamine.2. Facile synthesis of CdS/C core-shell nanospheres with ultrathin carbon layer for enhanced photocatalytic properties and stabilityCdS/C core-shell nanospheres have been synthesized successfully by a facile one-pot hydrothermal process. The as-prepared CdS/C core-shell nanospheres are with 100 nm in diameter and the amorphous carbon shell is with several nanometers in thickness. The phase, morphology and structures of the samples were investigated by X-ray power diffraction analyses, field-emission scanning electron microscopy and transmission electron microscopy; respectively. The as-prepared CdS/C core-shell nanospheres showed enhanced photocatalytic properties and photostability compared to the single counterpart of CdS nanospheres owing to the efficiently separation of photogenerated electrons (e-) and holes (h+) derived from the photocatalyst.3. Facile synthesis of Zno.sCdo.sS/C core-shell nanospheres with ultrathin carbon layer for enhanced photocatalytic properties and stabilityA facile template-free method has been developed for the fabrication of uniform Zno.sCdo.sS/C core-shell nanospheres with 100 nm in diameter and several nanometers of amorphous carbon shell in thickness regardless of the amount of glucose added (0.05-0.5). As expected, the as-prepared Zn0.5Cd0.5S/C core-shell nanospheres showed enhanced photocatalytic properties and photostability compared to the single counterpart of CdS and Zn0.5Cd0.5S nanospheres owing to the efficiently separation of photogenerated electrons (e-) and holes (h+) derived from the photocatalyst and the existence of the ultrathin carbon layer providing a surface for protection of the Zn0.5Cd0.5S core. |
