Showing papers by "Arghya Narayan Banerjee published in 2012"
TL;DR: In this paper, the authors reported the sol-gel synthesis of Gadoped anatase TiO2 nanoparticles and the photocatalytic oxidation of organic dye into nontoxic inorganic products under UV irradiation.
Abstract: Photocatalytic degradation of toxic organic chemicals is considered to be the most efficient green method for surface water treatment. We have reported the sol-gel synthesis of Gadoped anatase TiO2 nanoparticles and the photocatalytic oxidation of organic dye into nontoxic inorganic products under UV irradiation. Photodegradation experiments show very good photocatalytic activity of Ga-doped TiO2 nanoparticles with almost 90% degradation efficiency within 3 hrs of UV irradiation, which is faster than the undoped samples. Doping levels created within the bandgap of TiO2 act as trapping centers to suppress the photogenerated electron-hole recombination for proper and timely utilization of charge carriers for the generation of strong oxidizing radicals to degrade the organic dye. Photocatalytic degradation is found to follow the pseudo-first-order kinetics with the apparent 1st order rate constant around 1.3 × 10-2 min-1. The cost-effective, sol-gel-derived TiO2 :Ga nanoparticles can be used efficiently for light-assisted oxidation of toxic organic molecules in the surface water for environmental remediation.
63 citations
TL;DR: In this article, the use of an electrochemically active biofilm (EAB) for the synthesis of Au@TiO2 nanocomposite with sodium acetate as the electron donor was reported.
Abstract: Deposition of gold on titanium dioxide (TiO2) nanoparticles is highly beneficial for maximizing the efficiency of many photocatalytic reactions. In this study, we have reported for the first time the use of an electrochemically active biofilm (EAB) for the synthesis of Au@TiO2 nanocomposite with sodium acetate as the electron donor. The EAB acts as an electron generator for the reduction of gold ions on the surface of TiO2 nanoparticles. It was observed that the TiO2 plays not only as a support for the gold nanoparticles but also as a storage of electrons produced by the EAB within the particles. These stored electrons dramatically increase the reduction of gold ions and hence we have observed the formation of the Au@TiO2 nanocomposites within 90 min. A mechanism of the nanocomposite formation is also proposed. The as-synthesized nanocomposites were characterized by UV–Vis absorption spectroscopy to monitor the proper formation of the nanocomposites. X-ray diffraction and transmission electron microscopic analyses were performed to determine the structural and microstructural properties of the nanocomposites. High-resolution transmission electron micrographs depict the proper formation of the Au@TiO2 nanocomposites with gold nanoparticle size varying from 5 to 10 nm with an increase in the gold precursor concentration. Zeta potential measurements were used to investigate surface charges of the as-synthesized nanocomposites. This novel biogenic route represents a unique pathway for the low cost, eco-friendly, rapid, and controlled synthesis of nanostructured Au@TiO2 hybrid systems which will truly revolutionize the synthetic fields of nanocomposites.
37 citations
TL;DR: In this article, the room-temperature and size-dependent photoluminescence properties of CuAlO2 nanoparticles, deposited by a cost-effective direct current sputtering technique, have been studied.
Abstract: Photoluminescence properties of CuAlO2 nanoparticles, deposited by a cost-effective direct current sputtering technique, have been studied. The nanoparticles show room-temperature photoluminescence peaks of near-band-edge emission due to recombination of free excitons. A blue-shift in the emission peaks as a decreasing function of the nanoparticle sizes is observed, which is attributed to the quantum confinement effect within the CuAlO2 nanoparticles. Theoretical calculations of bandgap enhancement values are found to be matching fairly well with that of the experimentally obtained values, confirming the existence of the quantum size effect within the nanomaterial. Approximate calculations show that the confinement effect falls within moderate-to-weak confinement regime. X-ray diffraction and electron microscopic measurements confirm the proper phase formation and nanocrystalline structure of the as-deposited nanoparticles. The room-temperature and size-dependent photoluminescence properties of this nanomaterial will be very useful for light emitting diode and similar optoelectronic applications.
21 citations
TL;DR: A potentiostatic electrodeposition with much lesser deposition rate is considered to be the reason behind the very low and homogenous particle size distribution due to the lesser agglomeration of the authors' as-synthesized nanoparticles.
12 citations
TL;DR: In this paper, a site-specific fabrication of metal-incorporated graphitic microporous carbon terminated by highly ordered multilayer graphene walls via an ambient-temperature vacuum-based process is presented.
Abstract: The site-specific fabrication of metal-incorporated graphitic microporous carbon terminated by highly ordered multilayer graphene walls via an ambient-temperature vacuum-based process is presented for the first time. Sputtering of Cr nano-particles on the ultrathin amorphous carbon film manifests a dual effect of activation via dry-etching by the sputtering plasma and of ‘knock-on' inelastic collision between nanoparticles and C atoms for structural ordering. This novel and simple method is very useful for fabricating high surface area carbon nanostructures for hydrogen storage and clean energy applications. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
6 citations