Hydrothermal synthesis and polarized micro-Raman spectroscopy of copper molybdates

Polymorphism and Optical–Vibration Properties of MnV2O6·nH2O (n = 0, 2, 4) Prepared by Microwave Irradiation

“…Figure S2 (Supporting Information) presents SEM images for the polymorphs prepared at 110 °C, for 5–60 min. As it can be seen, rod-like morphology was confirmed for all times, which tend to grow by the “oriented attachment” mechanism, as previously observed by Dias et al − Figure shows TEM/HRTEM images for the MnV 2 O 6 ·4H 2 O prepared at 110 °C, for 60 min, where rod-like morphology (micrometer-sized in length) is observed in a low-magnification TEM image, as also verified previously for the coprecipitated sample. However, widths and thicknesses are much smaller than the observed for the coprecipitated vanadate, which are now on the order of dozens of nanometers.…”

“…Differently from the coprecipitated sample, these planes were easily identified in the rod-like materials showed by the low-magnification image (Figure ), which indicates that the microwave synthesis could be effective in producing materials with preferential growth directions. This result was recently observed by Dias et al, − who verified that the ac electrical fields during microwave irradiation can lead to an anisotropic growth of materials.…”

“…However, different band intensities are identified between samples, which could be an indication of disorder for materials prepared in shorter times. A better knowledge of the vibrational features for these hydrated phases can only be fully accessed by fitting procedures, and theoretical analysis for identifying the phonon modes. − Using the site symmetry and the site occupation factor of each atom of MnV 2 O 6 ·4H 2 O, group-theoretical tools were used to foreseen the Raman and infrared activities at the Brillouin-zone center (Γ), for the monoclinic C 2 /c space group. For this structure, Mn ions are in the 4d Wyckoff sites ( C i symmetry), while all the V, O, and H ions are in the 8f Wyckoff sites, with C 1 symmetry.…”

Facile Synthesis and Characterization of Cu3(MoO4)2(OH)2 Nanorods for High Performance Supercapacitor Electrode Application

“…[35,36] On the other hand, Cu 2 and Cu 3 do not relate to CuÀ O stretching modes since they were placed on inversion centers. [37,38] These results are further confirmed by Fourier transform infrared spectroscopic studies, shown in Figure 4.…”

“…The weak peak shown at 1628 cm À 1 and the peak at 3329 cm À 1 are ascribed to the infrared vibration of OH and HÀ OH (hydrogen bonding), respectively. The band appeared at 515 cm À 1 is due to v 3 vibration band [37][38][39][40] The basic characterization results such as XRD, Raman and FTIR confirmed the formation of Cu 3 ( MoO 4 ) 2 (OH) 2 samples through CTAB assisted hydrothermal method.…”