This work investigated the electrochemical characteristics of TiOx and its composite with reduced graphene oxide.

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Barium strontium titanate (BST) materials with the chemical formula of BaxSr1-xTiO3 had successfully made ​​by solid state reaction method. The materials were made in the form of bulk. Ba mole composition was varied in the value of x = 0,5; 0,7; and 0,9. It was varied to study the influence on crystal structure and dielectric constant. The result of crystalline characterization performed by X-ray diffractometer instrument shows that changes in the composition of x causes a shift in the diffraction angle. The lattice parameter was obtained from the refinement with the GSAS software and calculation process. Lattice parameter of BST with a value of x = 0,5 and 0,7 are a = b = c, so that the crystal structure is cubic. While the BST with a value of x = 0,9 has lattice parameter a = b ≠ c, so that the crystal structure is tetragonal. Dielectric constant measurements performed at frequency of 1 KHz by RLC-meter instrument. The highest dielectric constant ​was ​obtained at 465 on Ba0,9Sr0,1TiO3. The dielectric constant of cubic-crystal structured material is bigger than tetragonal-crystal structured material.

Abstract. Volatile organic compounds (VOC) such as benzene are among the most dangerous air pollutants emitted by chemical industry stacks, as they may contribute to environment and health issues. Lean catalytic oxidation of benzene has been considered as most proper method to abate it from the flue gas. This work developed nano-based copper oxide catalysts for lean oxidation of benzene. The aim of this study was to evaluate the activity performance of the nano-based copper oxide catalyst and compare to commercial catalyst. On the basis of the commercial catalyst, this study was also aimed to determine the reaction rate and its kinetic parameter. The oxidation of benzene was conducted in a fixed bed reactor at 300 o C, 1 atm, and GHSV of 15,000 h -1. The concentration of benzene in the feed and product were measured using online gas detector (Cosmos Gas Detector). The catalyst activity of nano-based copper oxide catalysts showed 20-30% conversion of benzene, while for commercial catalyst showed 86%. The reaction rate determination for first order reaction of benzene indicated that the activation energy was 48 kJ/mol with Arrhenius constant of 3x10 4 s -1.