Spectroscopic study of spinel ZnCr2O4 obtained from mechanically activated ZnO–Cr2O3 mixtures

Tuning the Electronic Bandgap: An Efficient Way To Improve the Electrocatalytic Activity of Carbon‐Supported Co3O4 Nanocrystals for Oxygen Reduction Reactions

“…To prove this conclusion, Raman spectra of these Co 3 O 4 /GCB hybrids were carried out and the obtained results are shown in Figure b. As observed, the Raman signals of these samples show five characteristic peaks at about 189, 470, 516, 609, and 679 cm −1 that correspond to the F 1 2g CoO 2 scissoring vibration and the E g , F 2 2g , F 3 2g , and A 1g symmetric Co−O stretching vibration modes, respectively . Relative to unloaded Co 3 O 4 , there is a positive shift in the Co−O band to higher wavenumbers for these hybrids.…”

Synthesis and Characterization of ZnCr2O4 Nanospinel Prepared via Homogeneous Precipitation Using Urea Hydrolysis

“…227). Zinc chromate is formed about 1200°C via solid‐state reaction . It can be seen that the calcination temperature for synthesizing crystallite ZnCr 2 O 4 by homogeneous precipitation is much lower than that by the solid‐state reaction.…”

Thermodynamic CoO–Co3O4 crossover using Raman spectroscopy in magnetic octahedron‐shaped nanocrystals

“…Some authors claim that this A 1g mode involves the symmetric stretching motion of the oxygen (‘breathing motion’) in the tetrahedral AO 4 group (sketched in Fig. , in the spinel Co 3 O 4 crystalline structure) or in the octahedral unit . Nevertheless, Laguna‐Bercero et al have suggested that the scenario is more complicated in spinels taking into account that the AO 4 units are not isolated from the rest of the lattice, and the A–O bonds are weaker than B–O bonds.…”