Direct sunlight-driven enhanced photocatalytic performance of V2O5 nanorods/ graphene oxide nanocomposites for the degradation of Victoria blue dye.

Herein, we report the synthesis and characterizations of Vanadium pentoxide (V2O5) nanorods/graphene oxide (GO) nanocomposite as efficient direct solar light driven photocatalyst for the enhanced degradation of victoria blue (VB) dye. The nanocomposite was synthesized by sonochemical process and characterized using several analytical methods in order to study the structural, morphological, compositional, optical and photocatalytic properties. The X-ray diffraction studies confirmed the orthorhombic structure of V2O5 while the morphological examinations revealed the growth of V2O5 nanorods and 2D GO sheets. Interestingly, the UV studies ratify that the bandgap of the nanocomposite was reduced compared to pure GO and V2O5. Interestingly, the interaction of the V2O5 nanorods with the graphene oxide substrate and its effect on the electronic properties of the combined system, have been examined by means of theoretical calculations, based on the so called Geometry, Frequency, Noncovalent, eXtended Tight Binding (GFN-xTB) method. Studying the photocatalytic behavior of nanocomposite, we observe an almost complete degradation (97.95%) of Victoria Blue (VB) dye under direct sunlight illumination within just 90 min. The outstanding nanocomposite photocatalytic efficiency was due to the excellent transfer of interfacial charge and the suppressed recombination of charge-carrier. The kinetics of the degradation process was also analyzed by calculating the rate constant and half-life time. Finally, a possible mechanism has also been discussed for the degradation process of VB dye using nanocomposite under direct sunlight irradiation.

A study of the structural, morphological, and optical properties of shock treated SnO2 nanoparticles: removal of Victoria blue dye.

In this work, Tin Oxide (SnO2) nanoparticles (NPs) were prepared by green microwave followed by hydrothermal methods, using tea extract as a reducing agent. To verify the stability of physical and chemical properties of SnO2 NPs, samples were subjected to shock impulsion experimentation. Different characterization techniques were employed to analyze the crystallinity, molecular structure, and optical parameters of the control SnO2 and shock wave exposed SnO2 NPs. Powder X-ray diffraction (PXRD) revealed no significant change in crystal structure. Williamson - Hall analysis demonstrates that the stress and strain between Sn-O changes during the impulsion of shocks. Rietveld analysis reveals change in the bond length between Sn-O. The molecular structure is not affected during shock loading, but the optical properties do change. From the photocatalytic experiment, we find that the parameters such as stress, strain, and bond length make an enormous impact in photocatalytic application.

Ni-Doped ZnO Thin Films: Deposition, Characterization and Photocatalytic Applications.

Root like structured Ni-doped zinc oxide [Zn(1-x)NixO (x = 0.09)] thin films were deposited on a non-conducting glass substrate by indigenously developed spray pyrolysis system at optimized substrate hotness of 573±5 K. Thus obtained Ni-doped ZnO thin films were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Atomic Force Microscopy (AFM). XRD result revealed that Ni-doped ZnO has a polycrystalline nature with a hexagonal wurtzite structure. For pure ZnO and Ni-doped ZnO thin films, the particle sizes were 60.9 and 53.3 nm while lattice strain values were 1.56×10-3 and 1.14×10-3, respectively. The film surface showed characteristic root-like structure as observed by the SEM. It was observed that the Ni-doped ZnO thin films were grown in high density along with more extent of branching as compared to pure ZnO thin films but retained the root-like morphologies, however, the branches were more-thinner and of shorter lengths. AFM analysis showed that the surface grains of the Ni-doped samples are homogeneous with less RMS roughness values compared with the undoped ZnO samples. The photocatalytic activity of the prepared thin films was evaluated by the degradation of methyl orange (MO) dye under UV light irradiation. Pure ZnO and Ni-doped ZnO thin films took 150 min and 100 min to degrade about 60% MO dye, respectively.

Structural, Optical and Magnetic Properties of Zn1-xCoxO Nanoparticles.

Zn1-xCoxO nanoparticles with three different values of 'x' (x = 0.05, 0.10, 0.15) were prepared by chemical co-precipitation process without any further heat treatment. The X-ray diffraction studies confirmed the wurtzite hexagonal crystal structure for synthesized Zn1-xCoxO nanoparticles. The dislocation density results reveal that there is an increase in the concentration of lattice imperfections with increasing the concentration of Co ions. The true values of lattice constants were calculated by using Nelson-Riley Function (NRF). Further, the average bond length (BL) were also calculated and presented. The optical and magnetic properties of Zn1-xCoxO nanoparticles were examined by room-temperature photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM), respectively. The calculated values of magnetic susceptibility for Zn1-xCoxO nanoparticles with x = 0.05, 0.10, 0.15 were found to be 9.883×10-4, 2.29×10-2 and 2.37×10-2, respectively.

Sunlight-Driven Photocatalytic Degradation of Methyl Orange Based on Bismuth Ferrite (BiFeO3) Heterostructures Composed of Interconnected Nanosheets.

Herein, we report the facile microwave-assisted synthesis, characterization and photocatalytic degradation applications of Bismuth ferrite heterostructures composed of interconnected nanosheets (BHNs). The synthesized materials were subjected to several analytical studies such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy and UV-visible spectroscopy in order to examine the morphological, structural, optical and photo catalytic properties. The structural and morphological characterizations confirmed the rhombohedral perovskite crystal structure and the formation of heterostructures composed of interconnected nanosheets for the synthesized material. The compositional characterization revealed that the synthesized material is bismuth ferrite with high purity. The BHNs were further used as efficient photocatalyst for the photocatalytic degradation of highly hazardous pollutant methyl orange under sunlight irradiation. The sunlight driven photocatalytic experiments revealed ~86% photodegradation of methyl orange dye in 150 min. The presented work revealed that the synthesized BHNs are excellent material for the photocatalytic degradation of various organic contaminants and hazardous pollutants.

Visible-Light Driven Photocatalytic Degradation of Eosin Yellow (EY) Dye Based on NiO-WO3 Nanoparticles.

Herein, we report a simple synthesis, characterization and photocatalytic degradation application of composite NiO-WO3 nanoparticles. The nanoparticles were synthesized by facile low-temperature method and characterized by several techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis diffuse reflectance spectra (DRS). The synthesized NiO-WO3 nanoparticles were used as efficient photocatalyst for the photocatalytic degradation of Eosin yellow (EY) dye. Interestingly, the synthesized photocatalytic exhibited a significant visible-light driven photocatalytic degradation of Eosin yellow (EY) dye. Under optimized conditions (pH = 5, catalyst dosage = 3 µM and initial dye concentration= 1.0 g/L), the obtained photo degradation of EY dye was above 95% in 180 min under visible light irradiation. Remarkably, reusability of the prepared photocatalyst was also observed and the photo-degradation reactions follow the pseudo-first-order model.