Characterisation of Copper (Ii) Oxide Synthesised by Precipitation Method
In this study, copper(I1) oxide (CuO) nanocrystalline powders were successfully synthesised via precipitation method. The main advantages of the method for the material preparation are the possibility of creating very pure materials and the flexibility of the process with respect to final product...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2005
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/6211/1/FS_2005_11.pdf |
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| Summary: | In this study, copper(I1) oxide (CuO) nanocrystalline powders were successfully
synthesised via precipitation method. The main advantages of the method for the
material preparation are the possibility of creating very pure materials and the
flexibility of the process with respect to final product quality. Synthesis parameters
which were concentration of copper, concentration of precipitating agent, pH and
types of precipitating agents were varied and their influence on the microstructural
properties of CuO were studied. Results showed that 1.0 M of copper nitrate,
Cu(NO& solution and 1.5 M of ammonium hydroxide, NH40H solution were the
most suitable molarities for its given the best precipitation yield and improved
microstructural properties. The calcination temperature of 623 K was chosen
because thermal gravimetric analysis revealed that the precursors fully transformed
to CuO at this temperature. As evidenced by X-ray diffraction analysis, all the
precursors were in copper hydroxyl nitrate phase and all the calcined samples were
pure CuO in 23-36 nm size with monoclinic structure. The FTlR spectra showed the
incorporation of nitrate and hydroxide anions into copper cations in the precipitation
process. CuO obtained from precipitation at pH 1.6 by using NH40H as precipitating agent showed the higher surface area, 8.7 m2 g-' in comparison with CuO prepared
from ammonium carbonate, (NH&C03 and sodium carbonate, Na2C03. For
precipitation finished at higher pH, i.e. pH 3.0 and pH 4.2, respectively, CuO
synthesised from Na2C03 possessed higher surface area in comparison with CuO
synthesised from NH40H and (NH4)2C03. From electron microscopy studies, tabular
crystallites with elongated hexagonal morphology were observed for the CuO
prepared by using NH40H. CuO precipitated from (NH4)2C03 were in platelet
morphology. Granular morphology was observed for the CuO prepared from
Na2CO;. Results of temperature-programmed reduction in hydrogen showed that the
total amount of oxygen removed from CuO was influenced by the surface area of
CuO. It was found that higher CuO surface area promised higher reducibility of CuO
due to the decreasing of crystallite size. |
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