ZnO For Degradation Research Articles

Functionalization of Calcium Sulfate/Bioglass Scaffolds with Zinc Oxide Whisker.

There are urgent demands for satisfactory antibacterial activity and mechanical properties of bone scaffolds. In this study, zinc oxide whisker (ZnOw) was introduced into calcium sulfate/bioglass scaffolds. Antimicrobial behavior was analyzed using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The results showed that the scaffolds presented a strong antibacterial activity after introducing ZnOw, due to the antibacterial factors released from the degradation of ZnO. Moreover, ZnOw was also found to have a distinct reinforcing effect on mechanical properties. This was ascribed to whisker pull-out, crack bridging, crack deflection, crack branching and other toughening mechanisms. In addition, the cell culture experiments showed that the scaffolds with ZnOw had a good biocompatibility.

Novel ZnO/Ag2CrO4 nanocomposites with n–n heterojunctions as excellent photocatalysts for degradation of different pollutants under visible light

Novel ZnO/Ag2CrO4 nanocomposites, as excellent visible-light-driven photocatalysts, were successfully prepared with different weight percents of Ag2CrO4 using a facile refluxing method at 96 °C. The phase, purity, morphology, and electronic properties of the resultant samples were characterized using XRD, EDX, SEM, TEM, UV–Vis DRS, FT-IR, and PL techniques. The nanocomposite with 30 % of Ag2CrO4 was selected as the best photocatalyst for degradation of rhodamine B under visible-light irradiation. Activity of this nanocomposite is about 16-, 20-, and 25-fold greater than that of the ZnO in degradation of rhodamine B, methylene blue, and methyl orange, respectively. The excellent activity of the nanocomposites was attributed to more visible-light absorption ability, due to presence of narrow band gap Ag2CrO4, and fast separation of the photogenerated charge carriers, due to formation of n–n heterojunctions between ZnO and Ag2CrO4. Furthermore, the influence of preparation time, calcination temperature, and scavengers of the reactive species on the photocatalytic activity was studied and the results were discussed.

Structure and optical properties of sequentially electrodeposited ZnO/Se bases for ETA solar cells

For a development of base layers for promising solar cells with extremely thin absorbers (ETA) low cost electrodeposition methods for sequential large-scale production of one-dimensional ZnO nanostructures and Se thin films with little material waste were investigated. Research of structure and optical properties of Se and ZnO have allowed us to choose electrolytes and modes in which electrodeposition of selenium was not accompanied by ZnO destruction. It was revealed that annealing of ZnO/Se samples using a halogen lamp provides conversion of amorphous selenious films into suitable for solar cells gray nanocrystalline hexagonal Se without ZnO degradation and thus enables the formation of bases of ETA solar cells.

Photoelectrochemical properties of electrochemically deposited metal chalcogenide/ZnO films

In this work we studied metal chalcogenide sensitization of ZnO by electrochemical deposition which provides a fine electric contact between metal sulfide and the oxide. Deposition conditions to prepare the CdS/ZnO and Ag2S/ZnO films with optimized photoelectrochemical (PEC) properties are investigated. Effect of deposition technique, time, Mn-doping and post-annealing on photoresponse of the fabricated films are discussed. A short circuit current density of 1.42mA/cm2 and an open circuit potential of −1.39V (overall power conversion efficiency of 0.81%) have been achieved for the annealed Mn-doped CdS/ZnO electrode which is prepared by potensiostatic deposition. Potensiostatic deposition yields Ag2S in Acanthite form which is accompanied by ZnO degradation and the photoelectrode exhibits considerably enhanced and widened light absorption but lower overall power-conversion efficiency.

Microwave Assisted Hydrothermal Synthesis and Characterization of N, S Co-Doped ZnO Photocatalyst

The N, S codoped ZnO was synthesized by microwave assisted hydrothermal method. The N, S codoping narrowed the band gap of ZnO (formed impurity states in the band gap), hence shift light response to range of visible light. Furthermore, the doped ZnO exhibits significantly higher photocatalytic activity than that of pure ZnO for degradation of reactive brilliant blue KN-R aqueous solution under simulative solar irradiation.

Hydrothermal Synthesis of ZnO/Zn Composites with Enhanced Photocatalytic Performance

ZnO/Zn composites photocatalysts were prepared by hydrothermal method using Zn powder as raw material, and the morphology, structure, and photocatalytic performance of composites were investigated. The results showed that the ZnO nanoparticles were produced at the surface of Zn metal powder during hydrothermal process. The thickness of ZnO outer layer (internal metal-semiconductor interfaces) can be controlled by varying hydrothermal treatment time. The resulting ZnO/Zn composites exhibit significantly higher photocatalytic activity than that of pure ZnO for degradation of anthraquinone dye (reactive brilliant blue KN-R) aqueous solution under ultraviolet light irradiation. The enhancement of photocatalytic performance of ZnO/Zn composites can be attributed to the formation of internal metal-semiconductor interfaces. The designed fabrication procedure is simple, feasible, and universal for a series of oxide/metal with controlled microstructure and improved performances.