Cerium Acetate Hydrate Research Articles

Emission and vibration analysis of diesel engine fuelled diesel fuel containing metallic based nanoparticles

This experimental study reports the results of emission and vibration characteristics of compression ignition (CI) engine with variable compression ratios (VCR) using nanoparticles added to diesel fuels. Three different nanoparticles namely, titanium (IV) dioxide (TiO2), copper (II) nitrate (Cu(NO3)2) and cerium (III) acetate hydrate (Ce(CH3CO2)3·H2O) were used with conventional diesel fuel at the dosage of 25 ppm and 50 ppm in order to prepare the four different test fuels. The engine tests were implemented in a single cylinder diesel engine under 4 Nm and 8 Nm engine load at a constant engine speed of 1500 rpm and at compression ratios (CR) of 17:1 and 18:1. The results showed that nanoparticles addition in the diesel fuels in ppm level did not caused any complications in the physicochemical properties but a slightly increase in heating value and cetane number. In addition, the combined effect of titanium dioxides and cerium acetate hydrate nanoparticles significantly reduced pollutants emissions regardless of NOx emissions. Especially, addition of cerium acetate hydrate into the blend fuels has become a dominant factor in the reduction of the harmful exhaust emissions. Furthermore, it was revealed that sound pressure level of engine block decreased with the addition of nanoparticles into diesel fuel which is parallel to vibration results.

Controllable hydrothermal synthesis of bundled ZnO nanowires using cerium acetate hydrate precursors

ZnO nanowire arrays were grown by the hydrothermal decomposition of zinc acetate dehydrate in precursor solutions containing cerium acetate hydrate. The effects of the Ce precursor on the hydrothermal synthesis of ZnO nanowires were investigated as a function of the Ce concentration. It was found that all the samples exhibited preferential orientation toward the c-plane and the Ce precursor had no effect on the lattice constant in the ZnO nanowires. ZnO nanowires grown in solutions containing 1 and 2 at% Ce precursors were bent and bundled, suggesting that solutions containing adequate amounts of Ce precursors enable the top surfaces of the vertically aligned ZnO nanowires to be either positively or negatively charged, and that electrostatic interactions among these local charges causes bending and bundling of the ZnO nanowires. Thus, Ce precursors in the solutions can control the morphology of the ZnO nanowires, causing them to be bent and bundled. We suggest that the bundled ZnO is applicable to Dye-sensitized solar cells because it can be enhanced adsorbed dye amounts in devices.

Nano ceria as xylene sensor – Role of cerium precursor

Cerium oxide (CeO2) thin films were deposited on glass substrates by spray pyrolysis technique using three different precursors namely cerium chloride heptahydrate, cerium nitrate hexahydrate and cerium acetate hydrate. Structural, morphological, optical, electrical and sensing properties of the CeO2 thin films were examined. X-ray diffraction patterns of spray deposited CeO2 thin films confirmed the formation of polycrystalline cubic fluorite crystal structure. The surface morphologies of CeO2 films were observed using field emission scanning electron microscope. The optical band gap observed from luminescence spectra varied from 3.23 to 3.57 eV. Room temperature sensing characteristics of CeO2 thin films towards acetone, ethanol, xylene and toluene were observed. CeO2 thin film deposited using cerium acetate hydrate at 0.1 M concentration exhibited a better response towards xylene with fast response and recovery times of 224 and 13 s respectively at ambient temperature.

Combustion synthesis of CeO2 nanoparticles for aging and inhalation exposure studies

The continuous production of an aerosol of CeO2 nanoparticles is valuable for nanoparticle aging and inhalation exposure studies, compared with other synthesis processes that require subsequent handling and preparation of the aerosol which can alter nanoparticle properties. This paper describes a new method for producing CeO2 nanoparticles and a novel facility where a combustion synthesis system was integrated in-line with an atmospheric ultraviolet (UV) aging chamber and an inhalation exposure system. Poly-disperse CeO2 nanoparticles were continuously produced to demonstrate the capability of the integrated nanoparticle synthesis and delivery system. The CeO2 nanoparticles were products of combustion of cerium acetate hydrate, a solid-phase precursor, with gas-phase hydrogen, oxygen, and nitrogen reactants. Results for particle size, concentration, crystal structure, and morphology are presented for the CeO2 nanoparticles produced in this study with and without UV exposure in the aging chamber. The setup successfully demonstrated the capability to maintain a steady CeO2 particle number concentration throughout four hours of operation with ~90% of the particles less than 200nm in size, corresponding to a mass concentration of approximately 500μg/m3. The CeO2 nanoparticle morphology (including primary particle size and aggregate size) and crystalline phase showed minimal sensitivity to UV aging in the ambient urban environment used in the study. The results indicate other species co-produced in diesel fuel systems (where CeO2 nanoparticles are used as a fuel additive) or found in the urban atmosphere may be required to affect the aging of CeO2 nanoparticles observed in previous studies.

Preparation of ultra-fine Sm0.2Ce0.8O1.9 powder by a novel solid state reaction and fabrication of dense Sm0.2Ce0.8O1.9 electrolyte film

A novel solid state reaction was adopted to prepare Sm0.2Ce0.8O1.9 (SDC) powder. A mixed oxalate Sm0.2Ce0.8(C2O4)1.5·2H2O was synthesized by milling a mixture of cerium acetate hydrate, samarium acetate hydrate, and oxalic acid for 5h at room temperature. An ultra-fine SDC powder with the primary particle size of 5.5nm was obtained at 300°C. The ultra-low temperature for the formation of SDC phase was due to the atomic level mixture of the Sm3+ and Ce4+ ions. The crystal sizes of SDC powders at 300°C, 550°C, 800°C, and 1050°C were 5.5nm, 11.4nm, 24.1nm and 37.5nm, respectively. The sintering curves showed that the powder calcined at lower temperature was easier to be sintered owning to its smaller particle size. A solid oxide electrolytic cell (SOEC), comprising porous La0.8Sr0.2Cu0.1Fe0.9O3−δ (LSCF) for substrate, LSCF–SDC for active electrode, SDC for electrolyte, and LSCF–SDC for symmetric electrode, was fabricated by dip-coating and co-sintering techniques. An extremely dense SDC film with the thickness of 20μm was obtained at only 1200°C, which was about 100–300°C lower than the literatures׳ reports. The designed SOEC was proved to work effectively for decomposing NO (3500ppm, balanced in N2), 80% NO can be decomposed at 600°C.

Synthesis and characterization of CeO 2 nano-rods

Abstract We report a synthesis of two types of CeO 2 nano-rods via the facile and efficient hydrothermal process free from any surfactant and template. The synthesized nano-rods are chemically identified as CeO 2 with the standard fluorite structure but their morphologies are different. The nano-rods prepared with cerium nitrate hexahydrate and sodium phosphate are thicker and shorter with diameter of ∼30 nm and length of ∼100 nm, and those prepared with cerium acetate hydrate and dibasic sodium phosphate are thinner and longer with ∼10 nm in diameter and ∼400 nm in length. Microstructural analyses reveal that the two species of nano-rods have low-energy {111} surfaces and grow along the 〈112〉 direction. As a consequence of their morphologies, the two types of synthesized nano-rods exhibit excellent UV-absorption ability in comparison to the irregular CeO 2 nanoparticles.

Designing the morphology of ceria particles by precursor complexes

Ceria-based materials are widely used as catalysts, catalyst supports and electrolytes in many industrial applications. The morphological requirements of ceria particles vary depending on their applications. Here we show that complex morphologies of ceria particles can be achieved by using precursor complexes in the spray pyrolysis (SP) method. Three precursor complexes have been investigated: the complex of cerium acetate hydrate (CeA) and cerium nitrate hydrate (CeN); CeA and cerium ammonium nitrate (CeAN); and CeN and CeAN. Our results suggest that the morphological formation mechanism is highly correlated with the factors of precursor solubilities, solvent evaporation rates and precursor melting temperatures.

Characterization of Mesoporosity in Ceria Particles Using Electron Microscopy

The geometry and three-dimensional (3D) morphology of the ceria particles synthesized by spray pyrolysis (SP) from two different precursors--cerium acetate hydrate and cerium nitrate hydrate (CeA and CeN ceria particles)--were characterized by transmission electron microscopy and electron tomography. Results were compared with surface area measurements, confirming that the surface area of CeA ceria particles is twice as large as that of CeN ceria particles. This result was supported by 3D microstructural observations, which have revealed that CeA ceria particles contain open pores (connected to surfaces) and closed pores (embedded in particles), while CeN ceria particles only contained closed pores. This experimental result suggests that the type of porosity is controlled by the precursors and could be related to their melting temperature during the heating process in SP.

Oriented polycrystalline mesoporous CeO 2 with enhanced pore integrity

Mesoporous CeO 2 particles are synthesized using a sol–gel method involving Pluronic P123 or F127 tri-block copolymer and cerium acetate hydrate. Transmission electron microscopy reveals well defined meso-channels of about 10 nm in diameter and a wall framework consisting of highly oriented polycrystalline CeO 2. The [0 0 1] axis of the crystals is found to be aligned parallel to the meso-channels, and lattice coherency of [1 0 0] or [0 1 0] also exists in perpendicular plane to the channel. A cooperative self-assembly of the tri-block copolymer and Ce 4+ species is believed to occur, along with the precipitation of nano-crystalline CeO 2 in the sol–gel process. It is proposed that the preferential orientation may result from a favored linkage of the low-order Miller indices {0 0 1} planes of CeO 2 to the PEO segment in the PEO–PPO–PEO tri-block copolymer micelles. The unique structural characteristics of meso-CeO 2 appear to contribute to maintaining the pore integrity during the synthesis as well as in a post-fabrication in situ TEM heating test.