Enhanced Photocatalytic Degradation Activity of 2-D Graphitic Carbon Nitride-SnO2 Nanohybrids.

In this paper, we report on the facile synthesis of graphitic carbon nitride (g-C3N4)-tin oxide (SnO2) nanohybrid as an efficient photocatalyst prepared via sol-gel method. SnO2 nanoparticles are pointcontacted with g-C3N4. The results of physio-chemical characterizations such as SEM-EDAX, XRD, BET, FT-IR and UV-DRS spectra reveal the successful formation and integration of nanohybrid. The photocatalytic activity has been studied by using methylene-blue as a model dye for degradation. It has been observed that the pseudo-first order rate constant was increased up to 1.78 times compared with pure SnO2. The enhanced photocatalytic activity was ascribed from the inhibition of electron-hole recombination where g-C3N4 nanosheets acts as an electron receiver from SnO2 via point contact. This mechanism is further verified via photoluminescence spectra. Our results prominently show new insights and potential applications of g-C3N4-SnO2 nanohybrids in the waste water treatment and environmental remediation sectors.

Enhanced Photocatalytic Properties of Nanostructured WO3 Semiconductor-Photocatalyst Prepared via Hydrothermal Method.

Ground and distilled water-mediated tungsten trioxide (WO3) nanostructures are prepared via hydrothermal approach. The physical and surface chemical properties of catalyst are analyzed using XRD, SEM-EDAX, HR-TEM, FT-IR, UV-DRS, Zeta potential and photoluminescence spectroscopy. It is confirmed that ground water has high impacts on the materials properties such as crystallinity and morphology. HR-TEM results proved the transformation of single crystalline to polycrystalline for sample W1 and W3 respectively. The photocatalytic efficiency of the various catalyst was analyzed by the degradation of methylene blue as a probe dye-molecule which was monitored by UV-vis spectroscopy. The decolorization efficiency was observed as 1.14 times maximized in distilled water prepared catalyst when compared with ground water prepared catalyst. Moreover, the persulfate activation was found as 2.3 fold amplified in distilled water prepared catalyst when compared with other catalyst. On the development of various water-assisted WO3 semiconductor photocatalysis, this work can provide new insights into the design of novel photocatalyst for potential applications in the energy and environmental remediation sectors.

Influence of Morphology and Common Oxidants on the Photocatalytic Property of ß-SnWO4 Nanoparticles.

In this paper, we report a simple, cost effective and surfactant-free method for synthesizing different morphology of ß-SnWO4 with irregular, spherical, flake-like and leaf-like structures by using sonochemical method followed by calcination. A well dispersed and highly crystalline ß-SnWO4 crystallites with various sizes have been prepared. The samples were characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM), UV-vis spectroscopy, particle size and Zeta potential analyser. The SEM images reveal the successful preparation of an irregular, spherical, flake-like and leaf-like structure of ß-SnWO4. The absorption maximum of as-prepared different structures of ß-SnWO4 was observed in visible region. The degradation efficiency was found to be increased in leaf-like structures compared to irregular, spherical and flake-like structures of ß-SnWO4. Further, an enhanced photocatalytic effect was observed in leaf-like ß-SnWO4 nanoparticles while the common oxidants such as peroxomonosulphate (PMS), peroxodisulphate (PDS) and hydrogen peroxide (H2O2) were added. The degradation efficiency of these oxidants was found in the order of PMS > H2O2 > PDS. Generally these oxidants act as electron scavengers. From our experimental results, it is found that maximum efficiency of 93% was achieved when PMS was added. This shows the vital role of common oxidants in photocatalytic characteristics and their future applications in waste-water treatment.