Mohaseen S. Tamboli

Nanowires of silver-polyaniline nanocomposite synthesized via in situ polymerization and its novel functionality as an antibacterial agent.

Silver-polyaniline (Ag-PANI) nanocomposite was synthesized by in situ polymerization method using ammonium persulfate (APS) as an oxidizing agent in the presence of dodecylbenzene sulfonic acid (DBSA) and silver nitrate (AgNO(3)). The as synthesized Ag-PANI nanocomposite was characterized by using different analytical techniques such as UV-visible (UV-vis) and Fourier transform Infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), thermo gravimetric analysis (TGA), X-ray diffraction (XRD), and transmission electron microscopy (TEM). UV-visible spectra of the synthesized nanocomposite showed a sharp peak at ~420 nm corresponding to the surface plasmon resonance (SPR) of the silver nanoparticles (AgNPs) embedded in the polymer matrix which is overlapped by the polaronic peak of polyaniline appearing at that wavelength. Nanowires of Ag-PANI nanocomposite with diameter 50-70 nm were observed in FE-SEM and TEM. TGA has indicated an enhanced thermal stability of nanocomposite as compared to that of pure polymer. The Ag-PANI nanocomposite has shown an antibacterial activity against model organisms, a gram positive Bacillus subtilis NCIM 6633 in Mueller-Hinton (MH) medium, which is hitherto unattempted. The Ag-PANI nanocomposite with monodispersed AgNPs is considered to have potential applications in sensors, catalysis, batteries and electronic devices.

Self-assembled hierarchical nanostructures of Bi2WO6 for hydrogen production and dye degradation under solar light

Three dimensional (3D) hierarchical nanostructures of orthorhombic Bi2WO6 with unique morphologies were successfully synthesized by a solvothermal method. The precursor concentration plays a key role in the architecture of the hierarchical nanostructures. A peony flower-like morphology was obtained at higher precursor concentrations, and a red blood cell (RBC)-like morphology with average diameter of 1.5 μm was obtained at lower concentrations. These hierarchical nanostructures were assembled by self-alignment of 20 nm nanoplates. As their band gap is in the visible region, the photocatalytic activity of the Bi2WO6 hierarchical nanostructures for the production of hydrogen from glycerol, and the degradation of rhodamine B (RhB) and methylene blue (MB) under ambient conditions in the presence of solar light was investigated. The Bi2WO6 with peony flower morphology was observed to be the most efficient photocatalyst (H2: 7.40 mmol h−1 g−1, kRhB: 0.240 and kMB: 0.100) of the reported nanostructures. The higher activity of the peony flowers was due to their porous nature, high surface area and lower band gap. Such unique 3D nanostructures of Bi2WO6 have been fabricated for the first time, and their use as photocatalysts in the production of hydrogen from glycerol has hitherto not been attempted. These nanostructures may have potential in ferroelectric, piezoelectric, pyroelectric and nonlinear dielectric applications.

Ag:BiVO4 dendritic hybrid-architecture for high energy density symmetric supercapacitors

We demonstrate the fabrication of Ag:BiVO4 with a dendritic architecture by a template free hydrothermal method. Then, symmetric cells based on Ag:BiVO4 electrodes were assembled which exhibit an extended voltage window of up to 1.6 V with an excellent energy density of 2.63 mW h cm−3 (38.43 W h kg−1) and a power density of 558 mW cm−3 (8.1 kW kg−1).