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Báo cáo hóa học: " FTIR and Raman Spectroscopy of Carbon Nanoparticles in SiO2, ZnO and NiO Matrices"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: FTIR and Raman Spectroscopy of Carbon Nanoparticles in SiO2, ZnO and NiO Matrices | Nanoscale Res Lett 2008 3 421-426 DOI 10.1007 s11671-008-9172-y NANO EXPRESS FTIR and Raman Spectroscopy of Carbon Nanoparticles in SiO2 ZnO and NiO Matrices G. Katumba B. W. Mwakikunga T. R. Mothibinyane Received 25 July 2008 Accepted 11 September 2008 Published online 1 October 2008 to the authors 2008 Abstract Coatings of carbon nanoparticles dispersed in SiO2 ZnO and NiO matrices on aluminium substrates have been fabricated by a sol-gel technique. Spectrophotometry was used to determine the solar absorptance and the thermal emittance of the composite coatings with a view to apply these as selective solar absorber surfaces in solar thermal collectors. Cross-sectional high resolution transmission electron microscopy X-HRTEM was used to study the fine structure of the samples. Raman spectroscopy was used to estimate the grain size and crystallite size of the carbon clusters of the composite coatings. X-HRTEM studies revealed a nanometric grain size for all types of samples. The C-SiO2 C-ZnO and C-NiO coatings contained amorphous carbon nanoparticles embedded in nanocrystalline SiO2 ZnO and NiO matrices respectively. Selected area electron diffraction SAED showed that a small amount of Ni grains of 30 nm diameter also existed in the NiO matrix. The thermal emittances of the samples were 10 for C-SiO2 6 for the C-ZnO and 4 for the C-NiO samples. The solar absorptances were 95 G. Katumba El T. R. Mothibinyane CSIR National Laser Centre Building 46A P.O. Box 395 Pretoria 0001 South Africa e-mail gkatumba@csir.co.za B. W. Mwakikunga CSIR National Centre for Nano-Structured Materials Building 19B P.O. Box 395 Pretoria 0001 South Africa B. W. Mwakikunga School of Physics University of the Witwatersrand P O Wits 2050 Johannesburg South Africa B. W. Mwakikunga Department of Physics University of Malawi The Polytechnic P B 303 Chichiri Blantyre 3 Malawi 71 and 84 for the C-SiO2 C-ZnO and C-NiO samples respectively. Based on these results C-NiO samples proved to have the .