Effect of Calcination Temperature on the Structural, Thermodynamic, and Optical Properties of MoO₃ Nanoparticles

Abstract

Temperature dependence of the structural, thermodynamic, and optical properties of MoO 3 nanoparticles synthesized using sol-gel and sonication methods were studied. MoO 3 nanoparticles showed variation in crystallite shape from hexagonal to orthorhombic and crystallite size in the range 3.05-5.21 nm with bandgap in the range 4.11-4.36 eV with change in the calcination temperature and the method of synthesis. Rietveld refinement of the X-ray diffraction (XRD) data confirmed the crystallite phase transition with space group PE and Pbnm with change in the lattice parameter ratio. Activation energy was calculated using XRD and TGA-DSC (thermogravimetry-differential thermal analysis) data and was found to be close to 4 kJ/mol. The bandgap fluctuation was due to the size dependence of the blue shift, which indicates strong quantum confinement due to the Bohr radius effect. Optical parameters such as the extinction coefficient, refractive index, optical conductivity, dielectric functions, and Urbach energy were calculated and found to depend on electron-phonon interactions.

Quantum Effects Enter Semiconductor-Based SERS: Multiresonant MoO3·xH2O Quantum Dots Enabling Direct, Sensitive SERS Detection of Small Inorganic Molecules

“…To begin with, the emerald colloid exhibiting bright yellow emission upon excitation is obtained, with the mean diameter of the QDs estimated to be 2.2 nm according to particle size distribution diagram (Figure 2a). The average size of Mo-2 particles is much smaller than the reported Bohr radius of MoO 3 (4.81 nm 25 ). Thus, it is expected to trigger a strong quantum size effect, which may produce many interesting optical properties as will be addressed in later paragraphs.…”

Facile synthesis of zwitterionic surfactant‐assisted molybdenum oxide/reduced graphene oxide nanocomposite with enhanced photocatalytic and antimicrobial activities

“…The peak appeared at 987/cm is because of strong C═C bending present in rGO and 811/cm is due to stretching vibration of oxygen linked with metal atom (Mo O). [30] MoO 3 / rGO nanocomposite contains both rGO and MoO 3 peaks that confirm the formation of nanocomposite.…”

“…confirm the formation of MoO 3 /rGO nanocomposite with monoclinic crystal system MoO 3 . [30] The characteristic peak (001) is due to rGO, and the other two main peaks of (300) and (310) are because of MoO 3 . [30,36] The crystallite size of MoO 3 /rGO nanocomposite was calculated using Scherer Equation ( 19);…”

“…The mixture was centrifuged and washed at least twice using distilled water and then with methanol to eliminate the impurities like NH 3 . The product was then dried in an oven for 24 hr at 80 C. Once the molybdenum oxide was dried, it was further calcined at 450 C for 2 hr for the formation of molybdenum oxide, as shown in Equations ( 1)-(4) [30] :…”

Molybdenum dinitrosyl Schiff base complexes of dehydroacetic acid and thiourea derivatives: DFT‐experimental characterization and nosocomial anti‐infectious implications

“…In addition to biorelevant effects of this class of compounds, a well‐pronounced catalytic role in olefin metathesis has also been reported. In general, Mo frameworks have been found to be industrially and medicinally important scaffolds . Another important aspect of such complexes is their theoretical studies to describe various energy parameters of these compounds .…”