Title

SYNTHESIS AND CHARACTERIZATION OF Co-ZnO COMPOSITE

SYNTHESIS AND CHARACTERIZATION OF Co-ZnO COMPOSITE

Authorship

Brocchi, Eduardo.A.; S.Gonçalves, Mario Sergio; Moura, Francisco José

Brocchi, Eduardo.A.

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S.Gonçalves, Mario Sergio

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Moura, Francisco José

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DOI

10.5151/2594-5327-34567

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Abstract

The paper describes the preparation of composite Co-ZnO by preferential reduction with hydrogen. Initially we developed a thermodynamic assessment of the main reactions to the process such as pyrolysis of nitrates of cobalt and zinc, responsible for obtaining the respective oxides, and the reduction of hydrogen. The experimental study was performed to evaluate the effect of important variables (temperature and partial pressure of the reacting gas) on the kinetics of reduction reactions. There was the feasibility of establishing conditions occur where the preferential reduction of cobalt oxide in relation to zinc oxide. As an example may be mentioned that in the temperature range of the experiments of reduction of cobalt oxide (590K - 790K) were obtained from 20 conversions and 80% within an interval of time between 1 and 15 minutes using a hydrogen flow of 0.18 L / min. In turn, the composite can be obtained in the test conducted at a temperature of 590K by the time of 30 minutes kept the same flow. The properties of materials were carried out by X-ray diffraction, SEM / EDS and transmission electron microscopy, it is possible to identify relatively pure oxides and Co-ZnO composite very homogeneous and consists of particles on the nanometer scale, these features are desirable for such materials.

The paper describes the preparation of composite Co-ZnO by preferential reduction with hydrogen. Initially we developed a thermodynamic assessment of the main reactions to the process such as pyrolysis of nitrates of cobalt and zinc, responsible for obtaining the respective oxides, and the reduction of hydrogen. The experimental study was performed to evaluate the effect of important variables (temperature and partial pressure of the reacting gas) on the kinetics of reduction reactions. There was the feasibility of establishing conditions occur where the preferential reduction of cobalt oxide in relation to zinc oxide. As an example may be mentioned that in the temperature range of the experiments of reduction of cobalt oxide (590K - 790K) were obtained from 20 conversions and 80% within an interval of time between 1 and 15 minutes using a hydrogen flow of 0.18 L / min. In turn, the composite can be obtained in the test conducted at a temperature of 590K by the time of 30 minutes kept the same flow. The properties of materials were carried out by X-ray diffraction, SEM / EDS and transmission electron microscopy, it is possible to identify relatively pure oxides and Co-ZnO composite very homogeneous and consists of particles on the nanometer scale, these features are desirable for such materials.

Keywords

hydrogen reduction, Co-ZnO, Characterization, nanocomposite.

hydrogen reduction, Co-ZnO, Characterization, nanocomposite.