The IR spectra of bulk Nb2O5‚nH2O and niobia supported on SiO2, Al2O3, ZrO2, and TiO2 were recorded in the fundamental and overtone NbdO regions, as well as in the hydroxyl region, to develop a better understanding of the structural models of surface NbOx species. The coincidence of the IR and Raman fundamental NbdO frequency in Nb2O5/Al2O3, Nb2O5/ZrO2, and Nb2O5/TiO2 provides the strongest evi...

One-dimensional (1D) metal oxide nanomaterials, such as zinc oxide (ZnO) nanowires and nanobelts (or nanoribbons), have recently attracted immense attention due to their sizeand shape-dependent optical, mechanical, and electronic properties. In stark contrast, investigations of 1D zirconia (ZrO2) and hafnia (HfO2) nanomaterials remain unexploited largely because of the formidable challenges ass...

UV-visible diffuse reflectance spectroscopy was used to probe the electronic structure and domain size of tungsten oxide species in crystalline isopolytungstates, monoclinic WO3, and dispersed WOx species on ZrO2 surfaces. UV-visible absorption edge analysis, CO2 chemisorption, and Raman spectroscopic results show that three distinct regions of WOx coverage on ZrO2 supports appear with increasi...

The utilization of metal oxide-zeolite catalysts in the syngas-to-olefin reaction is a promising strategy for producing C2–C4 olefins from non-petroleum resources. However, effect crystal phase oxides on catalytic activity these still ambiguous. Herein, typical (ZnO/ZrO2) with different phases (monoclinic (m-ZrO2) and tetragonal (t-ZrO2)) were employed syngas conversion. (ZnO/m-ZrO2+SAPO-34) co...

The structures, processes of shrinkage, and phase composition of the compact system ZrO2-WC, obtained by hot pressing with the transmission of high current, are considered in the article. We found that as a result of compaction, the ZrO2-WC-ceramics have uniform density distribution, with the following optimal mode consolidation values T = 1,350°C, P = 30 MPa and t = 2 min. These conditions all...

zno and zro2 photo catalysts were synthesized by sol-gel auto combustion method. the products were characterized by x-ray diffraction (xrd) and scanning electron microscopy (sem). structural and morphological properties of nano particles were investigated and the average crystalline size of zno and zro2 was obtained 44 and 51 nm, respectively. also, photo catalytic degradation of nitro phenol f...

Sintered samples of monoclinic zirconia (α-ZrO2) have been irradiated at room temperature with 6.0-GeV Pb ions in the electronic slowing down regime. X-ray diffraction (XRD) and micro-Raman spectroscopy measurements showed unambiguously that a transition to the ‘metastable’ tetragonal phase (β-ZrO2) occurred at a fluence of 6.5x10 cm for a large electronic stopping power value (≈ 32.5 MeV μm). ...

The vapour phase selective conversion of glycerol to acetol at normal atmospheric pressure in a fixed-bed micro reactor was investigated over SO4 2 and WOx promoted ZrO2 and M-ZrO2 (M = Al2O3 or TiO2) solid acid catalysts. The investigated sulfate and tungstate ion promoted zirconia-based catalysts were prepared by both coprecipitation and impregnation methods and calcined at 923 K. The synthes...