Combustion synthesis of Co3O4 nanopowders intended for use as pigments in selective paintings for solar flat collectors

M. C. GARDEY MERINO,; R. BELDA; G. E. LASCALEA; J. M. MARTÍN MARTÍNEZ; P. G. VÁZQUEZ

Congreso; SBP Mat 2010; 2010

In this work, it was established that two proposed combustion synthesis techniques aresuitable for the production of fine Co3O4 powders: one using lysine (Lys) as a fuel and asecond employing aspartic acid (Asp) for the same purpose, and cobalt nitrate as a metalsource with an oxidizing anion.As assessed by X-ray diffraction (XRD), in the ashes of these combustion routes it isobserved a certain amount of CoO remaining. So, performing a further calcination in an openair oven at 500ºC for two hours, stabilized, pure Co3O4 nanopowders were obtained for bothprocesses. Then, a phase transformation from CoO to Co3O4 occurs during the calcinationfinal step.Combustion syntheses employing glycine or urea as fuels to produce Co3O4 particles weredescribed previously, but no other fuels have been studied for this purpose yet.Paintings containing Co3O4 as pigments were used to improve the energetic efficiency of flatsolar collectors because these pigments have a high solar absorption value in the range of