Microwave assisted growth of highly oriented vanadium oxides nanostructures: structural, vibrational and electrical properties

Abstract

The proposed work focuses on the effects of growth time and annealing on the physico-chemical performance of vanadium oxides nanostructures (VO-NSs) films synthesized by a novel single reaction microwave synthesis. Thin films of VO-NSs were produced on glass substrates by varying the growth time and annealing temperature. Structural studies revealed that VO-NSs of synthesized films of VO 2 (B) + V 6 O 13 , VO 2 (B), V 3 O 7 and V 2 O 5 were crystallized in the form of monoclinic, monoclinic, tetragonal and orthorhombic structures with predominant orientation along ( 110), ( 110), ( 330) and ( 001) lattice plane, respectively. SEM analysis revealed that the VO-NSs thin films are dense and have uniform morphological characteristics. Furthermore, Raman spectroscopy show that all the samples undergo changes in intensities and peak positions that reflect changes in electronic structure and the vibrational properties. Our results demonstrate that the control of time and annealing treatment has a significant effect on the stoichiometry and the crystallinity leading to the control of the structure, size and morphology of VO-NSs. Moreover, the I-V curves were clearly linear and symmetrical with respect to both axes, with increasing the growth time and annealing treatment are two crucial parameters to improve the electrical conductivity, which influences the electrical properties and affects the behavior of the synthesized nanostructures. This synthesis approach offers a novel and simple route to produce one-dimensional nanostructured metal oxides, which are suitable for a wide range of applications, especially energy storage devices.

Enhanced photoelectrochemical hydrogen production via linked BiVO4 nanoparticles on anodic WO3 nanocoral structures

“…6d. 38,39 As a result, V-0.3 showed BiVO 4 peaks at 326 and 374 cm −1 without any by-products, which were attributed to the asymmetric and symmetric deformation of VO 4 3− . 40 Therefore, 0.3 M of Bi and V is an optimal concentration as a BiVO 4 precursor for fabrication of high-quality BiVO 4 NPs.…”

Raman spectroscopy of Wadsley phases of vanadium oxide

“…VO 2 (B) is a weak Raman scatterer that may oxidize to V 2 O 5 under laser irradiation, so some reports provide incorrect spectra of this phase. 29,38,39 However, the correct data are also available for different samples 5,32,37,40,41 (Figure 1b and Figure S1(b-f) (Supporting Information)). The formation of VO 2 (B) is proved by X-ray diffraction (XRD) (Figure S2 (Supporting Information)).…”

“…According to the group symmetry analysis, VO 2 (B) (both LTP and HTP) has 18 Raman‐active phonon modes: 12A g + 6B g . VO 2 (B) is a weak Raman scatterer that may oxidize to V 2 O 5 under laser irradiation, so some reports provide incorrect spectra of this phase 29,38,39 . However, the correct data are also available for different samples 5,32,37,40,41 (Figure 1b and Figure S1(b–f) (Supporting Information)).…”