Synthesis Of CeO Research Articles

Deposition of CeO2 on TiO2 nanorods electrode by dielectric barrier discharge plasma to enhance the photoelectrochemical performance in high chloride salt system

• One-step deposition and synthesis of CeO 2 /TiO 2 -NRs electrode by DBD plasma. • A bond combined CeO 2 (1 1 1) with TiO 2 was formed in CeO 2 /TiO 2 -NRs electrode. • The proportion of Ce 3+ /Ce 4+ was increased by plasma modification to enhance oxygen vacancy. • Heterojunction was formed between TiO 2 and CeO 2 to have a narrower band gap. • DBD plasma promotes PEC performance of CeO 2 /TiO 2 -NRs in high chloride salt system. In this study, cerium oxide (CeO 2 ) was deposited on TiO 2 nanorods (TiO 2 -NRs) through the one-step deposition by using dielectric barrier discharge (DBD) plasma treatment, where this was a simple and efficient means of synthesizing a CeO 2 /TiO 2 -NR electrode. The results of X-ray diffraction indicated that CeO 2 (1 1 1) was successfully loaded on the TiO 2 -NRs, and the peak shifted in the positive direction after DBD discharge-induced modification, indicating that a bond between CeO 2 and TiO 2 had been formed in the CeO 2 /TiO 2 -NR electrode. Based on X-ray photoelectron spectroscopy, the ratio of Ce 3+ /Ce 4+ increased due to plasma modification to enhance the oxygen vacancy of the CeO 2 /TiO 2 -NRs in the lattice structure. The CeO 2 /TiO 2 -NR composite electrode delivered the best photoelectrochemical (PEC) performance at a modified input voltage of 45 V and a deposition time of 10 min due to DBD discharge. The efficiency of removal of phenol from simulated seawater with a high salt system yielded the highest value of 97.1% for the CeO 2 /TiO 2 -NR electrodes through the PEC process at 3 V and UV–visible irradiation. A mechanism of the PEC performance of the CeO 2 /TiO 2 -NRs electrode was proposed, whereby a heterojunction was formed between TiO 2 and CeO 2 to increase the effect of oxygen storage, and active chlorine ions were produced in the high chloride salt system to enhance the degradation of pollutants.

Synthesis of CeOx‐Decorated Pd/C Catalysts by Controlled Surface Reactions for Hydrogen Oxidation in Anion Exchange Membrane Fuel Cells

AbstractDue to the sluggish kinetics of the hydrogen oxidation reaction (HOR) in alkaline electrolytes, the development of more efficient HOR catalysts is essential for the next generation of anion‐exchange membrane fuel cells (AEMFCs). In this work, CeOx is selectively deposited onto carbon‐supported Pd nanoparticles by controlled surface reactions, aiming to enhance the homogenous distribution of CeOx and its preferential attachment to Pd nanoparticles, to achieve highly active CeOx‐Pd/C catalysts. The catalysts are characterized by inductively coupled plasma–atomic emission spectroscopy, X‐ray diffraction, high‐resolution transmission electron microscopy, scanning transmission electron microscopy (STEM), electron energy loss spectroscopy, and X‐ray photoelectron spectroscopy to confirm the bulk composition, phases present, morphology, elemental mapping, local oxidation, and surface chemical states, respectively. The intimate contact between Pd and CeOx is shown through high‐resolution STEM maps. The oxophilic nature of CeOx and its effect on Pd are probed by CO stripping. The interfacial contact area between CeOx and Pd nanoparticles is calculated for the first time and correlated to the electrochemical performance of the CeOx‐Pd/C catalysts. Highest recorded HOR specific exchange current (51.5 mA mg−1Pd) and H2–O2 AEMFC performance (peak power density of 1,169 mW cm−2 mgPd−1) are obtained with a CeOx‐Pd/C catalyst with Ce0.38/Pd bulk atomic ratio.

Synthesis of CeO2‐loaded titania nanotubes and its effect on the flame retardant property of epoxy resin

A series of CeO2‐loaded titania nanotubes (CeO2‐TNTs) hybrid materials with different CeO2 loadings were synthesized by co‐precipitation method and then incorporated into epoxy resin (EP) to prepare CeO2‐TNTs flame‐retardant epoxy nanocomposites. Structure and morphology characterization indicated the successful synthesis of CeO2‐TNTs. The effect of CeO2‐TNTs with different CeO2 loading capacity on the flame retardance of EP was compared and analyzed by the thermogravimetric analysis, Cone and Raman. The results showed that CeO2 loading could increase the carbon residue of nanocomposites, reduce the peak heat release rate (PHRR) and total heat release (THR), and improve the fire safety of EP. The residual carbon content of EP/0.1CeO2‐TNTs sample at 700°C reached 19.8% with the lowest degradation rate, and the PHRR and THR were reduced to 680 kW/m2 and 32.9 MJ/m2, respectively. Such a significant improvement in flame‐retardant properties for EP could be attributed to the protective effect of CeO2‐TNTs.

Synthesis of CeO2 nanoparticles with different morphologies and their properties as peroxidase mimic

AbstractThe overall objective of this work was to identify and determine the controlling factors of catalytic activity of CeO2 nanoparticles with different properties. Therefore, four kinds of CeO2 nanoparticles are successfully synthesized and used as peroxidase mimics. The results reveal that the catalytic activity is related to specific surface area and surface oxygen (Osur) content. For different CeO2 nanoparticles, specific surface area is the leading factor of catalytic activity. The catalytic activity increases with the increasing specific surface area. If the CeO2 nanoparticles have similar specific surface area, the less Osur contains, the lower catalytic activity will be. Meanwhile, crystallinity is not the influence factor of catalytic activity. Bamboo‐like CeO2 (B‐CeO2) nanoparticles show excellent catalytic activity and the reaction conditions are optimized. Furthermore, the catalytic activity of B‐CeO2 nanoparticles decreases very slightly after 15 cycles of the catalysis experiment. Therefore, B‐CeO2 nanoparticles can serve as effective recyclable peroxidase mimics.

Synthesis of CeO2 Porous Nanospheres with Tunable Pore and Particle Sizes and Their Adsorption to Methyl Orange

The catalytic performance of ceria oxide (CeO[Formula: see text] was greatly influenced by the materials’ structure and surface area. In this paper, CeO2 porous nanospheres (PNS) with tunable pore and sphere sizes were synthesized by a solvothermal method using diethylene glycol as reaction media. All the as-synthesized CeO2 PNS presented good adsorption capacity for methyl orange, which makes them potential application in waste water treatment conveniently and economically. The control over the sphere and pore sizes of CeO2 PNS was achieved by regulating the volume of water bubble in the reaction system, which supplied limited room for the assembling of preformed CeO2 small nano-precursors.

Synthesis of CeO 2 /Au/Ho nanostructures as novel and highly efficient visible light driven photocatalyst

Abstract Only 3–5% of the UV photon flux reaching the earth’s surface, therefore it would be hugely beneficial to extend the light absorption of CeO2 to the visible light region. The present work is focused on the CeO2/Au/Ho nanostructures to improve photo-catalytic activity of CeO2 under visible light. In the other word, photo-catalytic activity of CeO2 is improved by plasmonic effect of gold and co- sensitizer effect of holmium in visible region. It seems that cooperation between Au and Ho significantly improve degradation efficiency of CeO2. In addition, effect of different parameters such as surfactant and precipitating agent on morphology of final products were studied. Prepared products were characterized by different technics such as XRD, SEM, and TEM.

Non-Aqueous Synthesis of CeO<SUB>2</SUB> Nanoparticles Using Block Copolymer Micelles as Templates and Their Assembly Into Porous Structures with Enhanced Catalytic Activity

Non-Aqueous Synthesis of CeO<SUB>2</SUB> Nanoparticles Using Block Copolymer Micelles as Templates and Their Assembly Into Porous Structures with Enhanced Catalytic Activity

Synthesis of CeO2/e-HTiNbO5 Nanocomposite and Its Application for Photocatalytic Oxidation Desulfurization

Nanoscaled CeO2/e-HTiNbO5 composite was assembled by a facile process using colloidal TiNbO[Formula: see text] (e-HTiNbO5) nanosheet and CeO2 colloid as precursors at room temperature. The nanosheet e-HTiNbO5 was obtained through proton-exchange and exfoliation process from its parent KTiNbO5. The microstructures and properties of the as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Laser Raman spectroscopy (LRS), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS), etc. The photocatalytic activity of the obtained nanocomposite is evaluated by the adsorption and photocatalytic oxidation of ethyl mercaptan (EM) under natural light irradiation. The results show that CeO2 nanoparticles are dispersed uniformly on the surface of e-HTiNbO5 and the layered structure of e-HTiNbO5 nanosheet maintains integrity. The interaction between dispersed CeO2 particles and e-HTiNbO5 results in lower bandgap compared to its precursors, and the photocatalytic activity of CeO2/e-HTiNbO5 are enhanced under natural light irradiation.

Correction: One step in situ synthesis of CeO2 nanoparticles grown on reduced graphene oxide as an excellent fluorescent and photocatalyst material under sunlight irradiation.

Correction for 'One step in situ synthesis of CeO2 nanoparticles grown on reduced graphene oxide as an excellent fluorescent and photocatalyst material under sunlight irradiation' by Animesh Kumar Ojha et al., Phys. Chem. Chem. Phys., 2015, DOI: .

Synthesis of CeO<sub>2</sub>-SiO<sub>2</sub> Composite Nanoparticles by Coprecipitation Method and Dispersion Stability of their Suspension

A series of CeO2-SiO2composite nanoparticles with different cerium and silica (Ce/Si) mole ratios were synthesized via a coprecipitation method using cerium nitrate, tetraethylorthosilicate and ammonia as raw materials. X-ray diffraction (XRD), fourier transform infrared spectrology (FT-IR), thermogravimetry-differential scanning calorimetry (TG/DSC), transmission electron microscopy (TEM) and energy dispersive analysis of X-ray (EDAX) were used to characterize the CeO2-SiO2nanoparticles. With the increase of CeO2content, the crystal of CeO2grew up gradually and the average crystallite size of the CeO2decreased. There are Ce-O-Si bonds in the CeO2-SiO2composite nanoparticles. The particle size of the CeO2-SiO2composite nanoparticles with a Ce/Si mole ratio of 1 is about 20–30 nm. The dispersion stability of the CeO2-SiO2composite nanoparticles with a Ce/Si mole ratio of 1 was studied. It was found that cationic and nonionic surfactant could obviously affect the dispersion stability of suspension, but not the anion surfactant. A suspension with CeO2-SiO2composite nanoparticles at 0.1 wt% was added in 0.1 g/L cationic surfactant CTAB, and its pH value was adjusted within the range of 10-10.5. In this condition, the stable suspension without sedimentation time was successfully obtained.

Methanol Solvothermal Route to Size-Controllable Synthesis of CeO<SUB>2</SUB> with Electrochemical Performances

Methanol Solvothermal Route to Size-Controllable Synthesis of CeO<SUB>2</SUB> with Electrochemical Performances

Synthesis of CeO2‐Based Quantum Dots through a Polyol‐Hydrolysis Method for Fuel‐Borne Catalysts

AbstractThe transparent colloidal solutions of monodisperse CeO2‐based quantum dots (QDs) were prepared by heating a triethylene glycol (TEG) solution of Ce(NO3)3⋅6 H2O (and Fe(NO3)3⋅9 H2O) at 180 °C. The CeO2‐based QDs were characterized by X‐ray powder diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), UV/vis absorption spectra and Brunauer–Emmett–Teller (BET) surface area. CeO2‐based QDs with uniform particle size below 5 nm exhibit narrow size distribution, quantum effect, good re‐dispersion ability and high surface area. For the formation of these QDs, a polyol‐hydrolysis mechanism is proposed. CeO2 QDs are applied in fuel borne catalysts (FBCs) for diesel soot combustion, which exhibit excellent activity at a rather low temperature, owing to the homogeneous and large number of contact points between the catalyst and the soot. The doping with Fe can further improve the selectivity to CO2.

Synthesis of CeO 2–ZrO 2 solid solution by glycothermal method and its oxygen release capacity

The glycothermal (GT) reaction of Ce acetate and Zr alkoxide directly yielded CeO 2–ZrO 2 solid solutions in a region of low Ce content ≤40 mol%. Of the CeO 2–ZrO 2 solid solutions obtained by the GT method and subsequent calcination at 500 or 800 °C, the sample with 20 mol% Ce content had the largest BET surface area. This sample exhibited the highest Ce-based oxygen release capacity in the whole Ce/Zr composition range. The oxygen release capacities of CeO 2–ZrO 2 solid solutions synthesized by the GT method were much larger than those of the samples prepared by a coprecipitation (CP) method. The Reitveld analysis and the repetitive reduction–oxidation experiment indicated that the CeO 2–ZrO 2 solid solution synthesized by the GT method has a homogeneous structure as compared with that prepared by the CP method.

Synthesis of CeO 2/TiO 2 nanoparticles by laser ablation of Ti target in cerium (III) nitrate hexahydrate (Ce(NO 3) 3·6H 2O) aqueous solution

A new synthesis process, laser ablation in an aqueous solution of target material, was applied to synthesize nanostructured CeO 2/TiO 2 catalyst particles. Reactivity within the laser plume (plasma) can be used to synthesize CeO 2 from an aqueous solution, 2 M cerium (III) nitrate hexahydrate (Ce(NO 3) 3·6H 2O) aqueous solution, and to fabricate TiO 2 from Ti target. CeO 2/TiO 2 nanoparticles were successfully synthesized by the laser ablation of Ti target in 2 M cerium (III) nitrate hexahydrate (Ce(NO 3) 3·6H 2O) aqueous solution. Laser ablation of Ti in a liquid environment and chemical reactions of the solution within a plasma plume are discussed.

Synthesis of CeO 2, ZrO 2, Ce 0.5Zr 0.5O 2, and TiO 2 nanoparticles by a novel oil-in-water microemulsion reaction method and their use as catalyst support for CO oxidation

A novel and straightforward approach for the synthesis of mesoporous inorganic oxide nanoparticles, with a small particle size and high specific surface area is reported, by using oil-in-water microemulsions, in contrast to the typically used water-in-oil microemulsion method. The new strategy implies the use of organometallic precursors, dissolved in nanometer-scale oil droplets (stabilised by surfactant), and dispersed in a continuous aqueous phase. The potential of this approach is explored for producing nanocrystalline ceria, zirconia, ceria/zirconia mixed oxide and titania. Nanocrystalline cubic CeO 2 and Ce 0.5Zr 0.5O 2 were obtained under soft conditions, whilst ZrO 2 and TiO 2 presented wide X-ray diffraction peaks. The specific surface area (SSA) of the obtained materials was in the order of 200–370 m 2/g and the particle size was very small (∼2–3 nm). The materials were calcined at 400 °C after which a high SSA was maintained (100–150 m 2/g) and the crystallinity was improved, yielding tetragonal phases for both TiO 2 (anatase) and ZrO 2. The potential of the calcined materials as catalyst support was explored in the CO oxidation reaction by doping the oxides with Au (2 wt%). The obtained results demonstrate the feasibility of this approach for the preparation of various supports with high SSA for catalytic purposes.

Synthesis of CeO 2–MnO x mixed oxides and catalytic performance under oxygen-rich condition

Ce 0.5Zr 0.5O 2, Ce 0.5Zr 0.2Mn 0.3O 2 and Ce 0.5Mn 0.5O 2 were prepared by citric acid sol–gel method. The effect of manganese on the structural and redox properties of ceria-based mixed oxides was investigated by means of powder X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller analyses, temperature-programmed reduction and catalytic activity evaluation in the presence of excess O 2. The results showed that some Mn cations could enter into the ceria lattice to form solid solutions. Mn 3O 4 appeared due to the instability of the mixed oxides with increment of the Mn doping ratio while another oxide Mn 2O 3 is detected in the physical mixture of ceria and manganese oxide. These Mn-doped mixed oxides, especially Ce 0.5Mn 0.5O 2, presented better catalytic activities than Ce 0.5Zr 0.5O 2 and even Pt-loaded catalyst for total oxidation of C 3H 8 and oxidative sorption of NO in the presence of excess oxygen. The oxidation ability of Mn and the strong interaction between Mn and Ce were suggested to promote the oxygen storage/transport capacity of the mixed oxides as well as reactive adsorption of nitric oxide and hydrocarbons.

Synthesis of CeO2 Nanorods via Ultrasonication Assisted by Polyethylene Glycol

Polycrystalline CeO2 nanorods 5-10 nm in diameter and 50-150 nm in length were synthesized via ultrasonication using polyethylene glycol (PEG) as a structure-directing agent at room temperature. The properties of the CeO2 nanorods were characterized by TEM, EDS, XRD, XPS, FT-IR, TG, BET, and UV-vis spectroscopy. Various reaction parameters, such as the content of PEG, the molecular weight of PEG, the concentration of KOH, the pH value, and the sonication time, were investigated by a series of control experiments. The content of PEG, the molecular weight of PEG, and the sonication time were confirmed to be the crucial factors determining the formation of one-dimensional CeO2 nanorods. A possible ultrasonic formation mechanism has been suggested to explain the formation of CeO2 nanorods.

Mesoporous CeO 2: Synthesis by nanocasting, characterisation and catalytic properties

Mesoporous CeO 2 was synthesised by using CMK-3 carbon as a structure matrix. Nitrogen physisorption, powder X-ray diffraction, transmission electron microscopy (TEM), selected-area electron diffraction (SAED), energy-dispersive X-ray (EDX), X-ray absorption near-edge structure (XANES), and thermal (TG/MS) analysis were used for their characterisation. Methanol decomposition to hydrogen, CO, and methane was used as a catalytic test reaction. The obtained products exhibit uniform pores with a diameter of ca. 5 nm in a two-dimensional hexagonal periodic arrangement, as well as interparticle porosity, broadly distributed around ca. 35 nm; the specific surface area is 148 m 2 g −1. The pore walls are polycrystalline. The polycrystalline nature and high surface-to-volume ratio of the products is reflected in an increased signal intensity in X-ray absorption spectroscopy. The synthesis of CeO 2 from Ce(NO 3) 3 within the pores of the carbon matrix and the subsequent thermal combustion of the carbon is monitored by thermal analysis. Catalytic tests reveal that the activity of the mesoporous products in methanol decomposition are substantially higher than for a non-porous sample.

Synthesis of CeO 2@SiO 2 core–shell nanoparticles by water-in-oil microemulsion. Preparation of functional thin film

Synthesis of nanoparticles under restricted environment offered by water-in-oil (W/O) microemulsions provides excellent control over particle size and shape, and inter-particle spacing. Such an environment has been involved to synthesize silica nanoparticles with a CeO 2 core, so-called CeO 2@SiO 2. Aqueous fluids made up of ceria nanoparticles with a size close to 5 nm have been used as the water phase component. The starting CeO 2 sols and obtained CeO 2@SiO 2 nanoparticles have been characterized by dynamic light scattering (DLS), X-ray diffraction, scanning and transmission electron microscopy, and specific surface area measurements. The microemulsion process has been characterized by DLS. Preliminary results on CeO 2@SiO 2 thin films are presented.

Synthesis of CeO 2 nanoparticles by mechanochemical processing and the inhibiting action of NaCl on particle agglomeration

An alternative route for the synthesis of ceria nanoparticles by mechanochemical reaction with reactants containing crystalline water was proposed. The displacement reaction 2CeCl 3·6H 2O(s)+3Na 2CO 3·10H 2O(s)?Ce 2(CO 3) 3· nH 2O(s)+6NaCl(s)+(42− n)H 2O was induced in a mild manner during milling, and a subsequent calcination of the as-milled powder along with by-product NaCl led to the formation of ceria nanoparticles. It was suggested that the existence of by-product NaCl in as-milled powder could greatly decrease the aggregation of CeO 2 particles during calcination, which benefited the formation of finer crystal ceria. TEM analysis of ceria obtained by calcining and subsequently washing has shown that the crystallite particle sizes of CeO 2 were in the range of 40–70 nm and that only weak agglomeration of the nanoparticles was observed.