IRANIAN JOURNAL OF CATALYSIS Synthesis, characterization and photocatalytic activity of CeO2-SBA-15 (original) (raw)
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Journal of Rare Earths, 2018
CeO 2 nanoparticles (NPs) were synthesized in alkaline medium via the homogeneous precipitation method and were subsequently calcined at 80 °C/24h (assigned as CeO 2-80) and 500 °C/2 h (assigned as CeO 2-500). The as-prepared materials and the commercial ceria (assigned as CeO 2-com) were characterized using TGA-MS, XRD, SEM-EDX, UVvis DRS and IEP techniques. The photocatalytic performances of all obtained photocatalysts were assessed by the degradation of Congo red azo-dye (CR) under UVA-light irradiation at various environmental key factors (e.g., reaction time and calcination temperature). Results reveal that CeO 2 compounds crystalize with cubic phase. CeO 2-500 exhibits smaller crystallite size (9 nm vs 117 nm) than that of bare CeO 2-com. SEM analysis shows that the materials are spherical-like in shape NPs with strong assembly of CeO 2 NPs observed in the CeO 2-500 NPs. EDX analysis confirms the stoichiometry of CeO 2 NPs. UV-vis DRS measurement reveals that, CeO 2-500 NPs exhibits a red-shift of absorption band and a more narrow bandgap (2.6 eV vs 3.20 eV) than that of bare CeO 2-com. On the contrary, Urbach energy of Eu is found to be increased from 0.12 eV (CeO 2-com) to 0.17 eV (CeO 2-500), highlighting an increase of crystalline size and internal microstrain in the CeO 2-500 NPs sample. Zeta potential (IEP) of CeO 2-500 NPs is found to be 7.2. UVAlight-responsive photocatalytic activity is observed with CeO 2-500 NPs at a rate constant of 10 × 10-3 min-1 , which is four times higher than that of CeO 2-com (K app =2.4 × 10-3 min-1) for the degradation of CR. Pseudo-first-order kinetic model gives the best fit. On the basis of the energy band diagram positions, the enhanced photocatalytic performance of CeO 2-500 nano-catalyst can be ascribed to O 2 •− , • OH and R •+ as the primary oxidative species involved in the degradation of RC under UVA-light irradiation. Key word: CeO 2 NPs, Congo red, photocatalytic activity, Bandgap, Urbach energy of Eu, band theory.
Journal of Water and Environmental Nanotechnology, 2021
Nanocrystalline UV light induced composite CeO2:SiO2 with high surface area and low band gap energy were prepared in order to assess its photocatalytic degradation capacity of target pollutant (mixture of dyes). The complete mineralization of target dye pollutants (30 ppm) occurred within 150 min. when CeO2:SiO2 catalyst with optimum loading 0.4 g was used. Overall, the present system is economical, reproducible and highly efficient. Further the comparative study on photocatalytic efficiency of SiO2 and CeO2 was compared with composite CeO2:SiO2. The effect of various operational parameters used in degradation like concentration of dye, amount of photocatalyst and various catalyst has been studied on the rate of reaction. The recyclability of the photocatalyst, CeO2:SiO2 was performed up to four runs. The photodegradation of waste water pollutants was occurred nearly 96 % using CeO2:SiO2 nanoparticles. The removal of waste water pollutants was confirmed by UV spectrophotometer by diminishing the absorbance to zero within 120 min using CeO2:SiO2 nanoparticles. The synthesized catalyst was characterized by various analytical investigative techniques like UV-DRS, FTIR, XRD, SEM, TEM and BET.
Photocatalytic activity of biosynthesized CeO2 nano particles
SN Applied Sciences
This paper focuses on a cost effective and environment friendly technique for green synthesis of cerium oxide (CeO 2) nano particles from cerium (III) nitrate hexahydrate solution by co-precipitation method using the leaf extract of different species of Artemisia pallens which acts as reducing and capping agent. The prepared CeO 2 nano particles were characterized by XRD, TEM, FTIR, UV-Vis spectroscopy. The Photocatalytic activity of the prepared ceria powders was determined by their ability to degrade Methylene blue solution under UV-light radiation. The photo degradation result observed with 10 mg/L ceria at pH = 11 for 180 min have highest output and pseudo 1st order rate constant was 0.983.
Photocatalytic Activity under Weak Visible Light of Fe3+ Doped Mesoporous CeO2
Industrial & Engineering Chemistry Research, 2014
Mesoporous CeO 2 and Ce−Fe−O solid solutions with high content of hydroxyl groups were successfully synthesized using triblock copolymer P123 as the template and Ce(NO 3) 3 •6H 2 O and Fe(NO 3) 3 •9H 2 O as raw materials. The resultant samples were characterized by X-ray diffraction (XRD), N 2 adsorption−desorption, Raman, UV−vis, transmission electron microscopy, and Fourier transform infrared spectroscopy techniques. The X-ray diffraction results indicated that the synthesized samples exhibited cubic CeO 2 without impurities. The photocatalytic activities of the prepared samples were evaluated by the decomposition of Rhodamine B (RhB) dye under weak natural light irradiation. The results showed that the photocatalytic efficiency of mesoporous CeO 2 is higher than that of bulk CeO 2 , but lower than that of mesoporous Ce−Fe−O solid solution. Moreover, removing the template by extraction in ethanol leads to a much better photocatalyst compared with a calcinated one, due to the preservation of the hydroxyl groups on the mesoporous surface.
KnE Publishing ICBSA 2018 International Conference on Basic Sciences and Its Applications Volume 2019, 2019
The photocatalytic activity of cerium oxide increased after being doped with mesoporous silica. Increasing activity photocatalytic as shown from BET, TEM, and DRS UV Vis data. Results showed the surface area of Cerium oxide doped of mesoporous silica advanced from 97.44 to 736.88 m 2 g −1. High surface area caused increased photocatalytic activity. DRS UV VIS Analysis showed that cerium oxide nanoparticles band gap value of 2.43 eV and mesoporous silica band gap value 1.27 eV. The smaller bandgap results in effective photocatalysts used in visible light. Degradation methylene blue had done used photochatalyst Ceria, MS-Ce dan MMS-Ce, and visible irradiation. This study determines the optimum weight of Ceria, MS-Ce and MMS-Ce catalysts, optimum radiation time of Ceria, MS-Ce and MMS-Ce catalysts and the effectiveness of photodegradation of methylene blue, MS-Ce and MMS-Ce at optimum conditions. Degradation of Methylene blue was analyzed using a UV-Vis spectrometer. The results showed that the optimum conditions obtained were the optimum catalyst weight of Ceria, MS-Ce, and MMS-Ce, were 50 mg, 50 mg, and 40 mg. The optimum time for Ceria, MS-Ce and MMS-Ce photocatalyst degrades used visible light was 150 minutes, 300 minutes and 120 minutes. The effectiveness of methylene blue degradation using Ceria, MS-Ce and MMS-Ce photocatalysts was 68.85%, 97.38%, and 99.98%.
Applied Catalysis B: Environmental, 2014
In this study, the application of mesoporous CeO 2 and Pr doped CeO 2 (Ce Pr O) as photocatalysts for the degradation of Rhodamine B (RhB) from aqueous solution was investigated. Mesoporous CeO 2 and Ce Pr O were prepared using SBA-15 as template. The resultant samples were characterized by XRD, N 2 adsorption-desorption, Raman, UV-vis, TEM, FT-IR, and XPS techniques. The characterization results show that the synthesized Ce Pr O has a 2D hexagonal structure, similar to that of the template, and possesses numerous oxygen vacancies. It is worth mentioning that the visible light adsorption intensity of Ce Pr O is much higher than that of mesoporous ceria and bulk ceria, due to simultaneous formation of doping level and mesopores. The photodegradation of RhB illustrates that the synthesized mesoporous Ce Pr O, especially 45% Ce Pr O, performs excellent decolorization under weak daylight irradiation. Furthermore, a novel photodegradation mechanism was proposed based on the adsorption of H 2 O 2 over the oxygen vacancy.
Fundamentals and Catalytic Applications of CeO2-Based Materials
Chemical reviews, 2016
Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40(th) anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful th...
2013
Cerium oxide nanoparticles were prepared by a novel simple microemulsion procedure and sol-gel method. Using the Taguchi design method, the effective parameters were determined and optimized for CeO 2 nanoparticle synthesis. These nanoparticles were characterized by XRD, SEM, TEM, DLS, and BET. The data obtained by these analyses indicated that the microemulsion procedure produces finer particles (3.9 nm) with higher specific surface area in comparison with the sol-gel method. In addition, photocatalytic degradation behavior of the Reactive Orange 16 in aqueous solution with cerium oxide nanoparticles was studied successfully.
Enhanced photocatalytic activity of cobalt-doped CeO2 nanorods
Journal of Sol-Gel Science and Technology, 2012
In this paper, CeO 2 and cobalt-doped CeO 2 nanorods synthesized by surfactant free co-precipitation method. The microstructures of the synthesized products were characterized by XRD, FESEM and TEM. The structural properties of the grown nanorods have been investigated using electron diffraction and X-ray diffraction. High resolution transmission electron microscopy studies show the polycrystalline nature of the Co-doped cerium oxide nanorods with a length of about 300 nm and a diameter of about 10 nm were produced. The X-ray Photoelectron spectrum confirms the presence of cobalt in cerium oxide nanorods. From BET, the specific surface area of the CeO 2 (Co-doped) nanostructures (131 m 2 g -1 ) is found to be significantly higher than that of pure CeO 2 (52 m 2 g -1 ). The Co-doped cerium nanorods exhibit an excellent photocatalytic performance in rapidly degrading azodyes acid orange 7 (AO7) in aqueous solution under UV illumination.