Cerium Oxide Nanoparticles Catalyst for the Oxidation of Methanol

2019 ◽  
Vol 35 (5) ◽  
pp. 1539-1545
Author(s):  
Hossein Bayahia

This study outlines the synthesis of cerium oxide nanoparticles, their characterization and their activity in the oxidation of methanol. A simple and easy co-precipitation method was used for the preparation of cerium oxide, without any added surfactants. The physicochemical properties of the sample were studied using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The morphology and size of the catalyst was studied using SEM. EDX confirms the element content of the synthesized cerium oxide. The structure of CeO2 was confirmed using XRD. Thus, the reported CeO2 was an active catalyst for methanol oxidation to form formaldehyde at a temperature range of 523–753K in the gas phase. At 753K, the cerium oxide catalyst gave 53% formaldehyde selectivity, 57% methanol conversion and 31% formaldehyde yields.

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4424 ◽  
Author(s):  
Mehrdad Khatami ◽  
Mina Sarani ◽  
Faride Mosazadeh ◽  
Mohammadreza Rajabalipour ◽  
Alireza Izadi ◽  
...  

Nanoparticles of cerium oxide CeO2 are important nanomaterials with remarkable properties for use in both industrial and non-industrial fields. In a general way, doping of oxide nanometric with transition metals improves the properties of nanoparticles. In this study, nickel- doped cerium oxide nanoparticles were synthesized from Stevia rebaudiana extract. Both doped and non-doped nanoparticles were characterized by X-ray diffraction, Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray, Raman spectroscopy, and Vibrating-Sample Magnetometry analysis. According to X-ray diffraction, Raman and Energy Dispersive X-ray crystalline and single phase of CeO2 and Ni doped CeO2 nanoparticles exhibiting fluorite structure with F2g mode were synthesized. Field Emission Scanning Electron Microscopy shows that CeO2 and Ni doped nanoparticles have spherical shape and sizes ranging of 8 to 10 nm. Ni doping of CeO2 results in an increasing of magnetic properties. The enhancement of ultraviolet protector character via Ni doping of CeO2 is also discussed.


Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2596
Author(s):  
Nicusor Fifere ◽  
Anton Airinei ◽  
Marius Dobromir ◽  
Liviu Sacarescu ◽  
Simona I. Dunca

Cerium oxide nanoparticles were prepared by a precipitation method using Ce(IV) sulphate as precursor dispersed in glycerol with varying synthesis parameters such as temperature or precipitating agent. The structural and morphological characteristics of the obtained nanoparticles were investigated by X-ray diffraction, transmission electron microscopy, and diffuse reflectance spectroscopy. The crystallite size of the nanoparticles varied between 13 and 17 nm. The presence of Ce3+ and Ce4+ was proved by XPS data in the CeO2 samples and the conservation of the fluorite structure was evinced by X-ray diffractograms with a contraction of the lattice parameter, regardless of the size of the nanoparticle. From diffuse reflectance spectra, two band gap energy values for the direct transition were observed. Depending on the synthesis condition, the red shift of gap energy and the blue shift of Urbach energy with increasing content of Ce3+ were ascertained. The antibacterial tests revealed that the cerium oxide nanoparticles show good antimicrobial activity towards the common pathogens Escherichia coli and Staphylococcus aureus.


2021 ◽  
Vol 1 (3) ◽  
pp. 176-189
Author(s):  
Prathima Prabhu Tumkur ◽  
Nithin Krisshna Gunasekaran ◽  
Babu R. Lamani ◽  
Nicole Nazario Bayon ◽  
Krishnan Prabhakaran ◽  
...  

Due to its excellent physicochemical properties, cerium oxide (CeO2) has attracted much attention in recent years. CeO2 nanomaterials (nanoceria) are widely being used, which has resulted in them getting released to the environment, and exposure to humans (mostly via inhalation) is a major concern. In the present study, CeO2 nanoparticles were synthesized by hydroxide-mediated method and were further characterized by Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction Spectroscopy (XRD). Human lung epithelial (Beas-2B) cells were used to assess the cytotoxicity and biocompatibility activity of CeO2 nanoparticles. 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and Live/Dead assays were performed to determine the cytotoxicity and biocompatibility of CeO2 nanoparticles. Generation of reactive oxygen species (ROS) by cerium oxide nanoparticles was assessed by ROS assay. MTT assay and Live/Dead assays showed no significant induction of cell death even at higher concentrations (100 μg per 100 μL) upon exposure to Beas-2B cells. ROS assay revealed that CeO2 nanoparticles did not induce ROS that contribute to the oxidative stress and inflammation leading to various disease conditions. Thus, CeO2 nanoparticles could be used in various applications including biosensors, cancer therapy, catalytic converters, sunscreen, and drug delivery.


2018 ◽  
Author(s):  
Malatesh S. Pujar ◽  
Shirajahammad M. Hunagund ◽  
Vani R. Desai ◽  
Shivaprasadgouda Patil ◽  
Ashok H. Sidarai

2020 ◽  
Vol 11 (4) ◽  
pp. 477-483
Author(s):  
T. V. Fesenko ◽  
I. V. Laguta ◽  
O. M. Stavynska ◽  
O. I. Oranska

The aim of this work was to study composition and antioxidant/reducing properties of Vitex cannabifolia leaves extract and to characterize it as a possible active agent for green synthesis of cerium oxide nanoparticles (CeO2-NPs). The aim of the study was also to prepare CeO2-NPs and to investigate the particles sizes, texture and morphology. Antioxidant/reducing properties of Vitex cannabifolia leaves extract were studied using Folin-Chiocalteu and 2,2-diphenyl-1-picrylhydrazyl (DPPH) tests, composition of the extract was explored by means of laser desorption/ionization time-of-flight mass spectrometry method. The extract was found to possess very high antioxidant/reducing capability, showing fast reduction of DPPH radicals even at 100-fold dilution. The main components of the extract were phenolic acids, flavonoids and terpenes; all these compounds are known to be active reducing and/ or stabilizing agents in green synthesis of various nanoparticles. Using the extract, CeO2-NPs were prepared by means of the procedure that included the reduction of cerium(IV) ammonium nitrate by extract components followed by annealing the precipitate at 600 °C under in air conditions. The particles synthesized were characterized by means of scanning electron microscopy, X-ray diffraction and nitrogen adsorption methods. According to X-ray diffraction and electron microscopy data, CeO2-NPs had crystalline structure, spherical form and fairly uniform particles size distribution; surface area of the particles was estimated from nitrogen adsorption isotherms as about 30 m2 per 1 g. The average crystallite size determined from X-ray line broadening data was about 17 nm, the average particles diameter derived from surface area data was up to ~30 nm. Thus, one can conclude that the particles synthesized are small enough to be suitable for biomedical applications while Vitex cannabifolia extract is the effective reagent for green synthesis of cerium oxide nanoparticles


A simple cost effective preparation of Magnesium oxide nanoparticles in nanotube morphology is reported using Chemical co-precipitation method. As prepared magnesium oxide nanoparticles were characterized using UV-visible spectroscopy, X-ray Diffraction, Field Emission Scanning Electron Microscope and Energy dispersive X-ray spectroscopy. As prepared magnesium oxide nanoparticles were found in nanotube morphology whose inner and outer diameter were 31 nm and 78 nm. The band gap of as prepared nanotubes were found to be 5.37eV with maximum absorbance at 200 nm.


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