Article: Preparation and physicochemical characterisation of thermally stable nano-sized hopcalite catalysts Journal: International Journal of Nanomanufacturing (IJNM) 2009 Vol.4 No.1/2/3/4 pp.159 - 165 Abstract: Hopcalite catalyst precursors were prepared by coprecipitation under constant pH and temperature. The thermal behaviour of catalyst precursor was investigated using TG and DTA. The crystal structure and solid-solid interactions were studied using powder X-ray diffraction (PXRD). The particle sizes of the prepared solids were computed using Scherer equation. The surface area of the prepared catalysts using adsorption of nitrogen at 77K and the catalytic activity towards CO oxidation by O2 were investigated. The computed values for the crystallite size of Cu1.5Mn1.5O4 phase ranged between 52 nm and 80 nm for all solid samples. The produced Cu1.5Mn1.5O4 phase remained as a nanocrystalline solid even by heating at 950°C. The kinetics of thermal decomposition of catalyst precursors suggest a mechanism for the solid-solid interaction between these oxides and clarify the formation of nanosized hopcalite spinel. The activation energy data derived from thermal kinetics revealed that the best chemical composition of the hopcalite system which shows a large surface area and higher catalytic activity is that with Cu/Mn = 3. Inderscience Publishers - linking academia, business and industry through research

Title: Preparation and physicochemical characterisation of thermally stable nano-sized hopcalite catalysts

Authors: S.N. Basahel, E.H. El-Mossalamy, M. Mokhtar

Addresses: Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, P.O. Box 80203, Saudi Arabia. ' Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, P.O. Box 80203, Saudi Arabia. ' Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, P.O. Box 80203, Saudi Arabia

Abstract: Hopcalite catalyst precursors were prepared by coprecipitation under constant pH and temperature. The thermal behaviour of catalyst precursor was investigated using TG and DTA. The crystal structure and solid-solid interactions were studied using powder X-ray diffraction (PXRD). The particle sizes of the prepared solids were computed using Scherer equation. The surface area of the prepared catalysts using adsorption of nitrogen at 77K and the catalytic activity towards CO oxidation by O₂ were investigated. The computed values for the crystallite size of Cu_1.5Mn_1.5O₄ phase ranged between 52 nm and 80 nm for all solid samples. The produced Cu_1.5Mn_1.5O₄ phase remained as a nanocrystalline solid even by heating at 950°C. The kinetics of thermal decomposition of catalyst precursors suggest a mechanism for the solid-solid interaction between these oxides and clarify the formation of nanosized hopcalite spinel. The activation energy data derived from thermal kinetics revealed that the best chemical composition of the hopcalite system which shows a large surface area and higher catalytic activity is that with Cu/Mn = 3.

Keywords: hopcalite catalysts; Cu1.5Mn1.5O4; thermal behaviour; X-ray diffraction; XRD; nitrogen adsorption; carbon monoxide oxidation; crystal structure; solid-solid interactions; nanotechnology; nanostructures.

DOI: 10.1504/IJNM.2009.028122

International Journal of Nanomanufacturing, 2009 Vol.4 No.1/2/3/4, pp.159 - 165

Published online: 07 Sep 2009 *

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Title: Preparation and physicochemical characterisation of thermally stable nano-sized hopcalite catalysts

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