TITLE:
Solid State Reactions in Cr2O3-ZnO Nanoparticles Synthesized by Triethanolamine Chemical Precipitation
AUTHORS:
Imelda Esparza, Myriam Paredes, Roberto Martinez, Adriana Gaona-Couto, Guadalupe Sanchez-Loredo, Luisa M. Flores-Velez, Octavio Dominguez
KEYWORDS:
Nanometric ZrCr2O4 Spinel, Cr-ZnO Nanoparticles, Thermal Analysis, FTIR, Chemical Preparation
JOURNAL NAME:
Materials Sciences and Applications,
Vol.2 No.11,
November
16,
2011
ABSTRACT: The present work reports the preliminary results about solid state reactions of Cr-ZnO solid solutions and ZnCr2O4 nanometric particles obtained with triethanolamine (TEA). Different compositions were prepared from 0.65 to 33.3 at % chromium, the last one corresponding to ZnCr2O4 cubic spinel composition. Fourier Transform Infrared Spectroscopy (FTIR) together with X-ray diffraction (XRD) patterns of powders with Cr3+ between 0.65 and 16.0 at % were assigned to Cr-ZnO solid solution due to the only presence of ZnO structure, FTIR spectra indicating that Cr-O bonding exists even if there was no presence of ZnCr2O4. With low chromium atomic percent, lattice parameters increase, but as the chromium content exceeds of 3 at %, there is basically no further expansion of the cell. From Williamson-Hall and Rietveld methods the lattice dimensions were assigned to chromium incorporation in ZnO structure and the lattice contraction by particle size refinement. After annealing all samples from 0.65 to 16.0 at % at 400°C in oxygen, the analysis showed that nanoparticles of Cr-ZnO solid solution still remain.