Microwave-Assisted Synthesis Of Metal-Sulfide Nanocomposite With Enhanced Photocatalytic Activity

Nowadays, environment and energy issues become more and more prominent, which human beings have to face with it. Meanwhile, the influence of environmental pollution attracts much attention in our daily life. Especially, the water pollution has become one of the global problems which need to be solved urgently. The traditional methods for water pollution can be broadly divided into three categories:physical adsorption, chemical treatment and biodegradation. These conventional processes have played important roles in the water treatment and environmental protection. However, due to inherent drawbacks in these methods, such as high power cost, long operation period, low efficiency and secondary pollution limit the wide utility in the industrialization production. As an environment-friendly technology for the water pollution, photocatalysis has recently attracted enormous research interest due to its excellent performance in environmental protection. Based on this excellent technology, some active species such as·OH and·O2-emerge on the surface of the semiconductor materials which can be activated under the irradiation of sunlight. Metal-sulfide nanocomposite is considered as a series of important photocatalytic material because of its high efficiency in the degradation of organic dyes and heavy metal ions in wastewater treatment process. This article pays attention to the preparation of various metal-sulfide nanocomposites. What is more, the photocatalytic activity for the degradation of the orgnic pollutes using the as-prepared nanocomposites as photocatalyst was further investigated. The contents of this paper were as following:1. Microwave-Assisted Synthesis of Porous Ag2S-Ag Hybrid Nanotubes with High Visible-Light Photocatalytic ActivityIn this chapter, we have rationally developed a facile one-pot microwave-assisted method to synthesize porous Ag2S-Ag heterostructure nanotubes with uniform morphology and good structural stability. The as-prepared hybrid structures manifest excellent photocatalytic activity for degradation of MO and reduction of aqueous Cr(VI). Furthermore, the optimal synergistic effect between Ag2S and Ag has been investigated through the generation of OH radicals in different hybrid photocatalysts. This work represents a good example of fabricating nanostructured materials using the facile microwave-assisted method. The versatile approach demonstrated in the present work could potentially be extended to synthesize other hybrid hollow nanostructures for different applications.2. Microwave-Assisted Formation of CdO/CdS Core-Shell Mesoporous Nanoboxes with Enhanced Visible-Light-Driven Photocatalytic Reduction of Cr(VI)In this work, porous CdO-CdS core-shell nanoboxes with uniform morphology and good structural stability were facilely prepared by microwave-assisted in situ surface sulfidation of CdCO3nanocubes followed by annealing treatment. The as-obtained products exhibit much higher visible-light-driven photocatalytic activity in the reduction of aqueous Cr(VI) than pure CdS. It is believed that this novel strategy is highly scalable, and can be extended for the fabrication of other binary porous hybrids with well-defined non-spherical shapes on large scales by using perfect carbonate templates.3. Microwave-assisted synthesis of CdS-reduced graphene oxide composites with enhanced photocatalytic activityIn this section, CdS-rGO composites are successfully prepared via microwave-assisted process which is regarded as a facile and rapid method for synthesizing nanocomposites. Furthermore, the photocatalytic activity of different photocatalysis are investigated. The experimental results indicate that CdS-rGO composites exhibit much higher photocatalytic activity for degradation of RhB and reduction of aqueous Cr(VI) than pure CdS.