Ferrospinel catalyst samples containing Nickel, Cobalt and Copper have been synthesized by room temperature co-precipitation route and have been found to be effective for the oxidative removal of carbon monoxide from automobile exhaust gases even at relatively lower temperatures (cold-start). These catalyst materials have been characterized by modern physico-chemical techniques such as XRD, TG, BET-BJH and SEM etc. Nitrogen adsorption studies shows the samples are mesoporous in nature with pore diameter of 5 - 10 nm. The catalytic efficiencies of these materials of having various compositions have been tested in a series of temperature programmed oxidation reactions involving carbon monoxide and the results discussed

The metal complex, [Ni(en) 2 (H 2 O) 2 ](NO 3 ) 2 (en = ethylenediamine), was decomposed in a static furnace at 200°C by autogenous decomposition to obtain phase pure metallic nickel nanocrystallites. The nickel metal thus obtained was studied by XRD, IR spectra, SEM and CHN analysis. The nickel crystallites are in the nanometer range as indicated by XRD studies. The IR spectral studies and CHN analyses show that the surface is covered with a nitrogen containing species. Thermogravimetric mass gain shows that the product purity is high (93%). The formed nickel is stable and resistant to oxidation up to 350°C probably due to the coverage of nitrogen containing species. Activation energy for the oxidation of the prepared nickel nanocrystallites was determined by non-isothermal methods and was found to depend on the conversion ratio. The oxidation kinetics of the nickel crystallites obeyed a Johnson-Mehl-Avrami mechanism probably due to the special morphology and crystallite strain present on the metal.

Pore volume and wet impregnations were carried on c-Al 2 O 3 support spheres using [Ni(H 2 O) 6 ](NO 3 ) 2 and [Ni(en) 2 (H 2 O) 2 ]X 2 complexes, where en ¼ ethylenediamine and X ¼ NO À 3 , Cl À , or CH 3 COO À . The distribution of nickel on the support was studied by optical microscopy and SEM-EDX. The use of ethylenediamine complexes leads to samples with nearly uniform profiles. The distribution is dependent on interaction of complexes with alumina, changes in viscosity during drying, and crystallization volume. Redistribution during drying is minimal for the ethylenediamine complexes. The study illustrates that increase in viscosity retards the convection distribution to outward migration. Cyclohexanol decomposition was studied as a test reaction and the results demonstrate that the macrodistribution of nickel oxide phase influences the product distribution.