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Mixed oxide

About: Mixed oxide is a research topic. Over the lifetime, 5224 publications have been published within this topic receiving 115567 citations.


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Journal ArticleDOI
01 Jan 2013
TL;DR: The results indicated that the ZrO(2) nanocrystals obtained by MCM show high crystallinity and uniform size distribution than the ones prepared by CCM, and the kinetics of PCD was found to follow pseudo first-order.
Abstract: ZrO(2) nanocrystals were synthesized by the microwave combustion method (MCM) using urea as the fuel without using any template, catalyst or surfactant. For the purpose of comparison, it was also prepared using the conventional combustion method (CCM). The as-synthesized ZrO(2) was characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), high resolution scanning electron microscopy (HR-SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. The results indicated that the ZrO(2) nanocrystals obtained by MCM show high crystallinity and uniform size distribution than the ones prepared by CCM. Hence, the influence of the preparation methods on the structure, morphology and optical activity of ZrO(2) was investigated systematically. Photocatalytic degradation (PCD) of 4-Chlorophenol (4-CP), a potent endocrine disrupting chemical in aqueous medium was investigated by ZrO(2) nanocrystals obtained by MCM. The kinetics of PCD was found to follow pseudo first-order. Having established that ZrO(2) was photo catalytically active, the mixed oxide catalysts of ZrO(2)-TiO(2) were also tested for the PCD of 4-CP.

118 citations

Journal ArticleDOI
TL;DR: In this paper, the depth concentration profile of the oxidized layers was measured by Rutherford Backscattering Spectrometry (RBS) and showed that at temperatures between 750 and 900°C, a two-layer structure was formed, consisting generally in a protective superficial layer of Al 2 O 3 with traces of Ti, followed by a titanium-rich zone.
Abstract: (Ti,Al)N coatings prepared by combined DC and RF magnetron sputtering were annealed in air at temperatures between 500 and 900°C, in order to obtain information regarding the oxidation behaviour. The depth concentration profile of the oxidized layers was measured by Rutherford Backscattering Spectrometry (RBS). During the heat treatment at 500°C, the Ti 0.35 Al 0.65 N coating forms a Ti and Al mixed oxide with about 10 at% of nitrogen. After the annealing at 600°C of Ti 0.62 Al 0.38 N and Ti 0.35 Al 0.65 N coatings, the nitrogen amount disappears and the oxide layer is still homogeneous. At temperatures between 750 and 900°C, a two-layer structure is formed, consisting generally in a protective superficial layer of Al 2 O 3 with traces of Ti, followed by a titanium-rich zone. The Ti 0.35 Al 0.65 N system showed a slightly higher oxidation resistance than the Ti 0.62 Al 0.38 N one. On the other hand, the Al-rich coating, Ti 0.19 Al 0.81 N, revealed the worst oxidation resistance, similar to the AlN coating, and the oxide layer is always homogeneous.

118 citations

Journal ArticleDOI
TL;DR: In this article, the Tafel slope of mixed oxide electrodes of general composition Ru0.3Ti(0.7−x)Ce 0.5−x was used as a model reaction to investigate the dependence of the electrocatalytic properties on oxide composition.
Abstract: Mixed oxide electrodes of general composition Ru0.3Ti(0.7−x)Ce x O2 were prepared by thermal decomposition of the respective chlorides using Ti as a support. x was varied between 0 and 70 mol %. Oxygen evolution was used as a model reaction to investigate the dependence of the electrocatalytic properties on oxide composition. Kinetics was studied by quasistationary current-potential curves and reaction order determination. A minimum Tafel slope of about 30 mV has been found in the 10–30% CeO2 composition range. On the basis of a zero reaction order at constant overpotential, a reaction mechanism has been proposed accounting for the composition dependence of the Tafel slope. It has been concluded that the replacement of TiO2 with CeO2 brings about an increase in the electrocatalytic activity for oxygen evolution, while the layer becomes more prone to mechanical erosion.

117 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of palladium metal on the performance of a CuO-ZnO-Al2O3 catalyst is studied for methanol synthesis by hydrogenation of carbon dioxide.

117 citations

Journal ArticleDOI
TL;DR: In this paper, a series of WO 3 -doped Mn-Zr mixed oxide catalysts were investigated for the selective catalytic reduction of NO x by NH 3 (NH 3 -SCR).

116 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202318
202265
2021184
2020198
2019175
2018178