Studies on structural, morphological, and optical properties of Cr2O3 nanoparticles: Synthesized via one step combustion process by different fuels

Abstract

This research presents a novel one-step solution combustion synthesis to obtain nano-structured Cr2O3 from chrome nitrate solution and one fuel such as aspartic acid (Asp) or Lysine (Lys), or trihydroxymethylamino methane (Tris) or ethylenediaminetetraacetic acid (Edta). Once obtained, the ashes were calcined at 500°C. The powders were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy with Fourier transform (FTIR), UV-Visible Spectroscopy (UV-VIS) spectroscopy and Brunauer-Emmett-Teller (BET) techniques. These powders will be used in solar absorbing surfaces: in composites (o cermets) and painted coatings. Within the obtained ashes and calcined powders, it was identified a Cr2O3 crystalline structure corresponding to the rhombohedral system and to the R-3c spatial group. The average crystallite size was determined for ashes and calcined powders, this value was in nanometric range between 29 and 45 nm, where for ashes were in general minor than calcined powders in all cases. It is probable that with an increment of the temperature, crystallite size would grow. A specific area of 167 m2/g was determined for asp-ashes. This was a highest value observed in specific literature and it could be used in catalysis reactions, while the area values of ashes was higher than calcined powders value for each fuel. The average particle size observed through TEM resulted in 50 nm to 100 nm approximately. The determined Energy band gap resulted in 3.055eV to 3.078 eV approximately. The Energy band gap slightly increased with calcination temperature. Further trials and investigation will confirm the mentioned tendencies.