K. Madhusudan Reddy

Tailored conductivity behavior in nanocrystalline nickel ferrite

In this letter, we report an important issue in nanoparticle synthesis by the “bottom up” approach. By controlling the pH of the starting mixture of the salts we have been successful in obtaining the desired conductivity of nanosized nickel ferrite. X-ray diffraction and transmission electron microscopy confirmed the size, structure, and morphology of the nanoferrites. All the materials are typical semiconducting oxides whose conductivity depends on the pH of the starting salt solution. Direct current and alternating current conductivity studies coupled with thermoelectric measurements and the resultant activation energies help us to propose the mechanism of conductivity in these ferrites. X-ray photoelectron spectroscopy studies are indicative of Ni3+ presence in p-type ferrite. The n- and p-type conductivity in these materials is attributed to the hopping due to the presence of Fe3+ and Ni3+ ions, respectively.

Photostabilization of dye on anatase titania nanoparticles by polymer capping

Abstract Nanoparticles of titanium dioxide (TiO2) were prepared by the sol–gel method and characterized by XRD, TEM, FTIR and UV-Visible absorption spectroscopy for their structure, morphology and particle size. Organization, stabilization of the nanoparticles of TiO2 from further growth, and partially inhibiting the photodegradation was achieved by capping with polymers. Photodegradation of dye on TiO2 nanoparticles encapsulated in different polymers has been studied by diffused reflectance UV spectroscopy. The role of the polymer on the photodegradation of TiO2 has been compared and explained.

Reforming of pyrolysis gasoline over platinum-alumina catalysts containing MFI type zeolites

Reforming of pyrolysis gasoline, a highly olefinic feed, has been carried out over Pt-alumina catalysts containing small amounts of MFI type zeolites. The incorporation of these zeolites helps in lowering the coke deposition on the catalysts, thereby increasing their life. Further, the products are virtually free of aliphatics. Due to the large concentration of aromatics in the feed, significant aromatic gain is obtained only at low pressures of operation.