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1.
Biomaterials having photoluminescent properties play a crucial role in real-time bioimaging after in vivo implantation. In this study, photoluminescence properties and decay characteristics of the borate-based 13–93B3 glasses containing different concentrations of cerium, gallium, and vanadium oxides were investigated for biomedical applications. The borate-based bioactive glass powders were prepared using melt-quench technique and size reduction was performed through planetary ball milling. Bioactivity of the prepared powders was investigated in simulated body fluid at 37 °C under static conditions. The photoluminescent properties and decay kinetics of the as-prepared and the SBF-treated bioactive glass powders were analyzed by steady-state and time-resolved photoluminescence measurements. Results revealed that the cerium activated glasses exhibited an intense luminescence centered at 538 nm. Broad-band emission of the gallium and vanadium doped samples was centered at 440 and 572 nm, respectively. All of the SBF-treated glasses exhibited enhanced lifetimes and bi-exponential decays both in nanosecond and microsecond regime measurements. It was concluded that depending on the dopant concentration, bioactive glass particles prepared in the study showed remarkable photoluminescence and have potential to be used in bioimaging applications. 相似文献
2.
《International Journal of Hydrogen Energy》2022,47(34):15480-15490
The rapid increase in energy consumption has severely rehabilitated human life urging to develop reliable and environmental friendly energy storage devices. Target oriented, systematic approach has been adopted to synthesis La doped CeO2 nanostructures with percentage as LaxCe1-xO2 (X = 0,1,3,5,7) for potential super capacitors applications. Morphological doping impact on H2 production, electrochemical and optical properties are thoroughly investigated. XRD studies revealed the crystalline phase purity and attained approximately 35 nm average crystallite size. The SEM images exposed that primary morphology nano-particles has been tuned into nanorods by increasing the La concentration in CeO2 with size range 40~60 nm. CV graphs depicted that the prepared electrodes obey the pseudo capacitive faradaic reactions behavior in nature. Maximum capacitance (925 F g-1) has been achieved by La0·05Ce0·95O2 which is better than numerous reported materials. The La0·05Ce0·95O2 also exhibited excellent GCD stability with 87.8% retention exhibiting it suitability for supercapacitor applications. Furthermore, the La0·05Ce0·95O2 showed the significantly higher H2 (9 μmol h?1g?1) production rate as compared to undoped CeO2 and La0·01Ce0·99O2, La0·03Ce0·97O2 samples. This higher production is attributed to the recombination rate and have strong substantial correlation with optical characteristics. 相似文献
3.
《Journal of the European Ceramic Society》2021,41(14):7105-7110
Gadolinium oxide ceramic powders were mixed to cerium oxide ceramic powders, pressed to pellets, and sintered either at 1450 °C or applying 200 V cm−1 electric field at 800 °C, 900 °C and 1000 °C. The structural phases and the microstructure of the sintered pellets were analyzed by X-ray diffraction and scanning electron microscopy, respectively. The formation of substitutional solid solution was followed by monitoring the increase of the electrical conductivity by impedance spectroscopy and X-ray diffraction. The main results show that Joule heating due to the flow through the pellets of the electric current, which was produced by the application of the electric field, allows for promoting partial solid solution as well as partial sintering the ceria-gadolinia pellets. Moreover, grain growth that occurred in the high temperature sintered pellets was inhibited in the electric field-assisted synthesized/sintered pellets, being an alternative technique for producing cerium oxide-gadolinium oxide solid solutions. 相似文献
4.
5.
Chencheng Wang Feng Chen Yuanzheng Tang Xiao Chen Junchao Qian Zhigang Chen 《Ceramics International》2018,44(6):5834-5841
Biologically structured carbon/cerium dioxide materials are synthesized by biological templates. The microscopic morphology, structure and the effects of different oxidation temperatures on materials are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) ultraviolet-visible light spectrum (UV–Vis) and X-ray Photoelectron Spectroscopy (XPS). Moreover, by splitting water under visible light irradiation, the hydrogen production is measured to test the photocatalytic property of these materials. The results show that materials made with bamboo biological templates which are immersed in 0.1 mol L?1 of cerium nitrate solution, then carbonizated in nitrogen (700 °C) and oxidized in air (500–600 °C), can obtain the biological structure of bamboo leaves. The product is in the composition of hybrid multilayer membrane, which one is carbon membrane form plant cell carbonation and another is ceria membrane by nanoparticle self assembly. The best oxidation temperature is 550 °C and the band gap of carbon/cerium dioxide materials synthesized at this optimum oxidation temperature could be reduced to 2.75 eV. After exposure to visible light for 6 h, the optimal hydrogen production is about 302 μmol g?1, which is much higher than that of pure CeO2. 相似文献
6.
Milli Suchita Kujur Vyasaraj Manakari Gururaj Parande Khin Sandar Tun Ashis Mallick Manoj Gupta 《Ceramics International》2018,44(13):15035-15043
Magnesium (Mg)-based nanocomposites owing to their low density and biocompatibility are being targeted for transportation and biomedical sectors. In order to support a sustainable environment, the prime aim of this study was to develop non-toxic magnesium-based nanocomposites for a wide spectrum of applications. To support this objective, cerium oxide nanoparticles (0.5?vol%, 1?vol%, and 1.5?vol%) reinforced Mg composites are developed in this study using blend-press-sinter powder metallurgy technique. The microstructural studies exhibited limited amounts of porosity in Mg and Mg-CeO2 samples (< 1%). Increasing presence of CeO2 nanoparticles (up to 1.5?vol%) led to a progressive increase in microhardness, dimensional stability, damping capacity and ignition resistance of magnesium. The compressive strengths increased with the increasing addition of the nanoparticles with a significant enhancement in the fracture strain (up to ~48%). Superior energy absorption was observed for all the composite samples prior to compressive fracture. Further, enhancement in thermal, mechanical and damping characteristics of pure Mg is correlated with microstructural changes due to the presence of the CeO2 nanoparticles. 相似文献
7.
《能源学会志》2020,93(2):666-678
Coal-fired power plant is the largest anthropogenic mercury source. Active carbon injection technique has been widely used to control the mercury emissions. However, high operation cost limits its development and it is necessary to find other potential mercury sorbents. In this study, raw semi-coke and a series of novel cerium (Ce) modified semi-cokes were synthesized and utilized for removing elemental mercury (Hg0) from simulated flue gas. It is noteworthy that the efficiencies were tested without hydrogen chloride (HCl) in order to evaluate the sorbents efficacy for low-chlorine (Cl) coal. The results show that the modified sorbents exhibited the best performance at 150 °C. The performance of sorbent could be reinforced due to the existence of oxygen (O2), nitric oxide (NO) and HCl. The adverse effect caused by sulfur dioxide (SO2) reduced dramatically after Ce modification. The negative impact of ammonia (NH3) on Hg0 removal in this study could be neglected owing to the tiny concentration of NH3. Raw semi-coke provided sufficient carbon content, which is favorable to mercury adsorption. As Ce loading increased, the carbon structure changed and the crystal of cerium oxide was formed in the modified semi-coke. The mass fraction of cerium oxide on the sorbent was over 4.4% when the concentration of Ce modification solution was higher than 0.2 mol L−1. The redox reaction activity and the oxygen storage ability of Ce3+/Ce4+ gave a huge boost to the performance of modified semi-coke. The addition of Ce also had an impact on the proportion of oxygen species. 相似文献
8.
Production of Synthesis Gas via Dry Reforming of Methane over Co‐Based Catalysts: Effect on H2/CO Ratio and Carbon Deposition 下载免费PDF全文
Ahmed A. Ibrahim Muhammad Awais Naeem Anis H. Fakeeha Wasim Ullah Khan Ahmed S. Al‐Fatesh Ahmed E. Abasaeed 《化学工程与技术》2015,38(8):1397-1405
The effect of support type on synthesis gas production using Co‐based catalysts supported over TiO2‐P25, Al2O3, SiO2, and CeO2 was investigated. The catalysts were prepared by the incipient wet impregnation method and characterized by various techniques for comparison. Experiments were performed in a micro tubular reactor. The results revealed that all Co‐supported catalysts produced synthesis gas ratios of 1 and below and, thus, proved to be well‐suited for methanol and Fischer‐Tropsch syntheses. Co catalysts supported over TiO2‐P25 and Al2O3 provided better synthesis gas ratios and stability performances. The promotion of a Co/TiO2‐P25 catalyst with Ce had a substantial influence on its catalytic activity and the amount of carbon deposit. A Ce‐promoted catalyst diminished markedly the extent of carbon deposition and thus boosted the performance towards better activity and stability. 相似文献
9.
《中国稀土学报(英文版)》2020,38(4):445-450
A spiropyran-based probe was developed.It serves as a fluorescence turn-on probe for selective detection of Ce~(3+) in both ethanol and aqueous(water/ethanol,1:9 or 9:1,v/v) media.Ce~(3+) can induce photochromism of the probe though the probe exhibits negligible photochromic property by itself.The probe is sensitive to Ce~(3+) and the detection limit reaches 1.7 μmol/L.It exhibits a high selectivity for Ce~(3+)ion over other common metal cations including Li~+,Na~+,Ag~+,Sr~(2+),Ni~(2+),Co~(2+),Hg~(2+),Zn~(2+),Cr~(3+),Al~(3+),Fe~(3+) and Bi~(3+) and lanthanide ions Nd~(3+),Yb~(3+) and La~(3+).The probe may be used for quantitative determination of the concentration of Ce~(3+) ion in a range of 1-10 μmol/L and for application to environmental water samples.Sensing mechanism of the probe towards Ce~(3+) ion is proposed. 相似文献
10.
《Current Opinion in Solid State & Materials Science》2015,19(2):69-76
Cerium-based oxide compounds are known for their wide range of applications in catalysis, corrosion prevention, electrochemical cells, photocatalysis, UV absorbers, biomaterials, microelectronics, optical devices, thermal coatings, and glass abrasives. The technological applications of these materials are possible due to a combination of the electronic structure of Ce and the size effects at the nanoscale. In particular, reversible transformation between the Ce(III) and Ce(IV) oxidation states on the surface of cerium oxides is critical to the functionality and potential uses of the materials. In this paper, the main technological applications of cerium-based oxide coatings are reviewed based on the work done to date. Special interest is placed on the emerging trends. 相似文献