1. Dijana Jelić, Medicinski fakultet Banja Luka ,
Republic of Srpska, Bosnia and Herzegovina
2. Branko Škundrić,
Republic of Srpska, Bosnia and Herzegovina
3. Slavko Mentus, Serbia
Abstract: Copper (II) oxide is widely used as a catalyst because of its high activity and selectivity in oxidation and reduction reactions, such as the oxidation of CO and hydrocarbons and the reduction of NOx in automobile exhaust systems. Copper oxide is also used in the synthesis of methanol from CO and H2 and in the water-gas shift reaction. Crystallite size, influencing specific surface area is a factor of catalytic activity, and it may be adjusted by a temperature pretreatment. In this study, we syntesized copper oxide by a gel combustion method. Very fine crystals such obtained were subjected to progressive coarsening by isothermal treatment at 400, 600 and 800°C in air atmosphere. SEM observations revealed that at 400 oC thread-like agglomerates, composed of ~100 nm particles were obtained, which upon treatment at 600 oC transform into huge island-like aglomerates composed of 100-500 nm particles, and upon treatment at 800 oC desintegrate to separate particles roughly 1-2 microns in size. The oxide samples were subjected to reduction to metallic copper, in a hydrogen atmosphere, under thermogravimetric control. The deceleration of reduction kinetics seems to be correlated with the mean particle size observed by SEM. The thermogravimetric data were used to calculate kinetic parameters of reduction in function of treatment temperature, using various kinetic models. The best fit of obtained experimental results was provided by use of expanded Prout-Thomkins formula. Since the reduction products obtained in this kinetic study is fine copper powder, this study can also be useful in designing of a commercial scale process for copper powder production.
Acknowledgement: This study is supported by the project F-190 of SASA, and by the Agreement on scientific cooperation between SANU and ASARS, no. 01-393/15
Ključne reči :
Tematska oblast:
SIMPOZIJUM A - Nauka materije, kondenzovane materije i fizika čvrstog stanja
Datum:
19.06.2018.
Contemporary Materials 2018 - Savremeni Materijali
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