M. Tanveer

Synthesis of CuS flowers exhibiting versatile photo-catalyst response

Hierarchically structured covellite copper sulfide (CuS) microflowers composed of nanosheets have been successfully fabricated via a one-pot sonochemical process, using copper sulfate and thiourea aqueous solution as precursors in the presence of citric acid, without any prefabricated template. Large-scaled architectures are homogeneous and quite separately displaced and assembled by pure hexagonal single-crystalline CuS nanosheets, having thickness within 20 nm. The as obtained hierarchical CuS structures possess rather high surface area and unique double pore size distributions measured from N2 adsorption isotherms. Moreover, a possible growth mechanism for the CuS hierarchical architectures is proposed on the basis of temporal evolution controlled experiments. Most importantly, these hierarchically structured CuS catalysts showed highly efficient and versatile photo-catalytic activities as well as excellent recyclability in degrading highly concentrated dye aqueous solutions of methylene blue (MB), rhodamine B (RhB) and their mixed solution (MB + RhB) with the help of hydrogen peroxide (H2O2) under natural light irradiation, suggesting a promising application in wastewater purification.

The synergistic effect between WO3 and g-C3N4 towards efficient visible-light-driven photocatalytic performance

We have developed a facile, scaled up, efficient and morphology-based novel WO3–g-C3N4 photocatalyst with different mass ratios of WO3 and g-C3N4. It was used for the photodegradation of rhodamine B (RhB) under visible light irradiation and it showed excellent enhanced photocatalytic efficiency as compared to pure g-C3N4 and WO3. The apparent performance of the composite/hybrid was 3.65 times greater than pure WO3 and 3.72 times greater than pure g-C3N4 respectively, and it was also found to be much higher than the previously reported ones. Furthermore, the optical properties of composite samples were evaluated. The bandgap of composite samples lies in the range of 2.3–2.5 eV, which was favourable for photodegradation. The possible mechanism for enhanced catalytic efficiency of the WO3–g-C3N4 photocatalyst is discussed in detail. It was found that the enhanced performance is due to the synergistic effect between the WO3 and g-C3N4 interface, improved optical absorption in the visible region and suitable band positions of WO3–g-C3N4 composites.

Facile synthesis of novel Nb3O7F nanoflowers, their optical and photocatalytic properties

Novel nanoflowers (NNF) of Nb3O7F have been synthesized by a facile template free route without using any surfactant. The evolution of these NNF have been studied by varying different reaction parameters. Using the UV-Vis spectra absorption peak the calculated bandgap was 2.9 eV. Organic dye rhodamine B (RhB) was degraded with average photodegradation efficiency of 87.8%, 94.23% and 99.7% with higher rate constant k = 1.1559, 1.9011 and 3.8862 for 0.005 g, 0.01 g and 0.1 g respectively. The rate constant for 0.1 g was found to be larger than for Nb2O5, commercial TiO2 Degussa P25, carbon modified Nb2O5/TiO2, g-C3N4, Fe2O3/g-C3N4 composites and SnNb2O6.

Atypical BiOCl/Bi 2 S 3 hetero-structures exhibiting remarkable photo-catalyst response

We demonstrate the fabrication of BiOCl/Bi2S3 which is well defined at a large scale. The BiOCl/Bi2S3 hetero-structures exhibit an enhanced photo-catalytic degradation of methyl orange (MO) compared to BiOCl and Bi2S3, attributed to the interface between Bi2S3 and BiOCl, which effectively separate the photo-induced electron-hole pairs and suppress their recombination.摘要本文首次合成了具有独特形貌的异质结构BiOCl/Bi2S3. 相对于单一的BiOCl和Bi2S3, BiOCl/Bi2S3异质结构能有效地分离光生电子-空穴对以及抑制它们的再结合, 从而表现出更好的光催化降解甲基橙性能.