Unique N doped Sn3O4 nanosheets as an efficient and stable photocatalyst for hydrogen generation under sunlight.

Unique N doped Sn3O4 nanosheets have been demonstrated successfully using a facile hydrothermal method. Investigations of the triclinic phase and the impurities were performed using powder X-ray diffraction analysis (XRD) and Raman spectroscopy. The morphological analysis demonstrated a rectangular intra- and inter-connected nanosheet-like structure. The length of the nanosheets was observed to be in the range of 200-300 nm and the thickness of the nanosheets was less than 10 nm. The optical study reveals an extended absorption edge into the visible region, owing to the incorporation of nitrogen into the lattice of Sn3O4, which was further confirmed using X-ray photoelectron spectroscopy (XPS). Considering the band structure in the visible region, the photocatalytic activities of pristine and N doped Sn3O4 nanosheets for hydrogen evolution from water under natural sunlight were investigated. 4% N-Sn3O4 showed a higher photocatalytic activity (654.33 µmol-1 h-1 0.1 g-1) for hydrogen production that was eight times that of pristine Sn3O4. The enhanced photocatalytic activity is attributed to the inhibition of charge carrier separation owing to the N doping, morphology and crystallinity of the N-Sn3O4 nanostructures. A stable efficiency was observed for three cycles, which clearly shows the stability of N-Sn3O4.

Fluorescent Carbon-Dots Thin Film for Fungal Detection and Bio-labeling Applications.

The fluorescence properties of CDs, such as high quantum yield, tunability of emission color, and so on, make a strong potential material in various fields. These applications are mainly derived from in situ formation of surface functional groups, high chemical stability, biocompatibility, and easy interaction with substrates, etc. Mostly, the research applications of CDs concentrate on the labeling of biological species, drug delivery, and sensing in consequent biomedical applications. However, the detection of the fungal species/spores present in the environment by using CDs is rarely reported. Herein, we demonstrate CDs-based thin film as a sensor for detection of fungal spores from the environment. The procedure of detection is based on fluorescence, observed in the film of carbon dots deposited on quartz plates by using the Blodgett technique. It is observed that the CDs film shows quenching in the fluorescence intensity by the substrate, namely, fungal spores' (Aspergillus niger, Penicillium chrysogenum, Alternaria alternata). The effective features of the present detector system are easy fabrication, low cost, high stability, and a green and economical procedure of synthesis. The process of detecting fungal spores even at low concentration from the atmosphere is relatively fast when compared to presently used methods. Finally, real-world feasibility of the sensor film is tested by its successful application for the determination of the presence fungal spores in the environment. Furthermore, CDs have been also successfully applied for the bio-labeling of Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacterial systems.