Topic
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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TL;DR: In this paper, an oxide capacitor consisting of BaTiO3 and an oxide is studied as a new type CO2 sensor based on capacitance change, and the optimum operating temperature and frequency for CuO-BaTiO 3 are 729 K and 100 Hz, respectively, and 80% response time to 2% CO2 is within 25 s.
Abstract: An oxide capacitor consisting of BaTiO3 and an oxide is studied as a new type CO2 sensor based on capacitance change. Sensitivity to CO2, as well as the optimum operating temperature, was strongly dependent on the particular oxide mixed with BaTiO3. Among the elements investigated in this study, CuO–BaTiO3 exhibited the highest sensitivity to CO2. In particular, the CuO–BaTiO3 mixed oxide at the equimolar composition is highly sensitive to CO2. The optimum operating temperature and frequency for CuO–BaTiO3 are 729 K and 100 Hz, respectively, and the 80% response time to 2% CO2 is within 25 s. The equimolar mixture of CuO and BaTiO3 can measure the CO2 concentration from 100 to 60 000 ppm. Carbonation of oxide seems to play a key role for the detection of CO2 on these mixed oxide capacitors. The optimum operating temperature of these mixed oxide capacitors for CO2 detection, therefore, correlates with the decomposition temperature of the carbonate corresponding to the oxide mixed with BaTiO3. The capacitance increase of CuO–BaTiO3 upon exposure to CO2 seems to result from the elevated height of the potential barrier at the grain boundary between CuO and BaTiO3. Carbonation of CuO in the element seems to bring about the elevation in the height of the potential barrier.
105 citations
TL;DR: In this paper, the structural and electrical properties of these aerogels are characterized after annealing using X-ray diffraction, Xray photoelectron spectroscopy, surface-area measurements, and impedance spectrographs.
Abstract: High-surface area RuO2−TiO2 is an important material for catalytic and power source technologies. To create this mixed oxide as a nanoscale, high-surface-area material, we have synthesized electrically conductive aerogels of RunTi1-nOx via sol−gel chemistry and supercritical drying of the resulting gel. The structural and electrical properties of these aerogels are characterized after annealing using X-ray diffraction, X-ray photoelectron spectroscopy, surface-area measurements, and impedance spectroscopy. Their properties are affected by the nature of the RuCl3 precursor and the initial sol-gel chemistry. Whereas bulk 32 mol % RuO2·TiO2 is an electronic conductor, a dominant ionic response is measured in the impedance of Ru0.32Ti0.68Ox aerogels. This impedance is ascribed to a proton conduction mechanism associated primarily with the hydrous surface of the RuOx component. The electrical conductivity of these Ru0.32Ti0.68Ox aerogels at 25 °C increases from 10-4 S cm-1 in ambient air to 10-2 S cm-1 under a...
104 citations
TL;DR: In this article, the authors showed that the catalysts prepared by impregnation method are more active than those prepared by gel impregnation method because of their higher degrees of metal dispersion and reducibility.
104 citations
TL;DR: In this article, the textural and structural changes in several CeZr1−xO2 mixed oxides were studied using the SBET and mean crystal size (D) curves.
104 citations
TL;DR: In this paper, hydrotalcite-derived catalysts promoted with Zr species were prepared via co-precipitation method, resulting in materials with various Zr loading.
Abstract: Hydrotalcite-derived catalysts promoted with Zr species were prepared via co-precipitation method, resulting in materials with various Zr loading. Physicochemical properties of catalysts precursors and final catalysts were investigated via XRF, XRD, low temperature N2 sorption, H2-TPR, CO2-TPD, TG, SEM and TEM techniques. So characterized catalysts were subsequently tested in the dry methane reforming reaction at 550 °C. Zr-loading introduced into brucite-like layers influenced the process of thermal decomposition of HTs and, as a result, their properties and performance in DRM. Although Zr promotion decreased activity, it strongly increased the stability and selectivity of the catalysts. The catalyst with Zr species present in the framework of periclase-like mixed oxide exhibited high resistance to coking due to the rearrangement of Ni particles upon DRM reaction.
104 citations