Effect Of Cerium Ions Research Articles

Effect of cerium ions in Ce-Doped ZnO nanostructures on their photocatalytic and picric acid chemical sensing

Nanostructured ZnO doped with different Ce precursor concentrations (1, 5 and 10 mol%) has been prepared via co-precipitation method and tested for their photocatalytic and chemical sensing performances toward methyl orange (MO) and picric acid (PA) chemicals, respectively. After addition of Ce dopant, the spherical morphology of ZnO particles changed to a cone-like structure and exhibited the single-phase wurtzite structure, except for the 10 mol % dopant concentration. Blue-shift was detected in 5 mol% Ce doping, and this was found to be the optimum concentration for achieving the maximum dye degradation and sensing performances. The 5 mol% Ce doped ZnO expressed the complete MO degradation under UV light illumination, but the decrease in MO degradation with 10 mol% Ce doped ZnO was suggested to suppress the Ce3+ character in the sample. Facile redox couple Ce3+/Ce4+ appeared to improve the charge separation of Ce-doped ZnO upon UV illumination, forming the basis for release of O2, leading to increased catalytic and PA sensing performances.

The Effect of Cerium Ions on the Structure, Porosity and Electrochemical Properties of Si/Zr-Based Hybrid Sol-Gel Coatings Deposited on Aluminum

This study was focused on the synthesis and characterization of Si/Zr-based hybrid sol-gel coatings with and without the addition of cerium(III) ions. The coatings were deposited on aluminum aiming to act as an effective and ecologically harmless alternative to toxic chromate coatings. The chemical composition, structure, thermal properties and porosity of the non-doped and Ce-doped coatings containing various Zr contents were examined by Raman spectroscopy and photothermal beam deflection spectroscopy. The corrosion properties of the coated aluminum substrates were studied using AC and DC electrochemical methods in 0.1 M NaCl electrolyte solution. Barrier and protecting properties of the coatings were monitored upon long-term immersion in chloride solution using electrochemical impedance spectroscopy. The effect of cerium ions was two-fold: on the formation of a more condensed Si−O−Zr network structure and on the formation of Ce-based deposits, which diminish the rate of cathodic reaction at the coating/metal interface. These effects acted synergistically and resulted in the creation of the coatings with effective barrier and active corrosion protection.

Effect of cerium ion (III) on corrosion resistance of organic–inorganic hybrid coating on surface of aluminum-tube used in refrigeration equipment

Organic–inorganic hybrid coating on the surface of aluminum-tube used in refrigeration equipment using cerium ion (III) as the additive was fabricated by sol–gel method, and the structure of the coating was confirmed by FT-IR. The results of the characterization show that the corrosion resistance of the coating with 1.5 mmol/L cerium ion (III) gains significant improvement, in which the colour retention time of CuSO4 extends to 500 s, the anti-acid and alkali corrosion rates reduce by 67% and 70% compared with the blank one, respectively, and the salt spray tests also show good corrosion resistance. The electrochemical tests demonstrate that the self-corrosion current density and potential of the sample with hybrid coating are about 2.877×10−7 A/cm2 and –0.550 V, respectively. The metallographic and SEM images show that the hybrid coating is uniform and dense, and the EDS analysis confirms that the coating is mainly composed of Al, Si and Ce elements.

Effect of cerium/18-crown-6-ether coordination complex OH[rad] quencher on the properties of sulfonated poly(ether ether ketone) fuel cell electrolyte membranes

The effect of cerium ions (Ce3+) on the anti-oxidation and other properties of sulfonated poly(ether ether ketone) (sPEEK) membrane was studied, as it quenches the hydroxyl radicals, the major oxidation promoter in fuel cell operation. Cerium (Ce) was introduced along with 18-crown-6-ether to form a coordination complex to prevent both the migration of Ce3+ ions from the membranes and the direct interaction with sulfonic acid groups in sPEEK. The chemical and physical structures of the composite membranes were investigated using FT-IR, 1H NMR, SEM, EDX, and SAXS. As the concentration of Ce3+ ions increased, the distance between ion clusters of the membranes decreased by reduction of the strength of sulfonic acids interacted with the Ce3+ ions. The introduction of Ce3+ ions reduced the proton conductivity, but the presence of 18-crown-6-ether lessened the effect. According to Fenton׳s test, the pristine sPEEK membrane was completely degraded by oxidation in 24h, but the composite membranes containing Ce3+/18-crown-6-ether complex were stable for up to 70h. Other properties such as the thermal and mechanical stability and the water uptake were not noticeably affected by the presence of Ce3+ at the low concentration level of 2mol% relative to sulfonic acid groups.

Synthesis and properties of high corrosion resistant Ni–cerium oxide nano‐composite coating

AbstractThe effect of cerium ion on the formation, morphology, composition, and corrosion behavior of Ni–cerium oxide coatings was investigated by SEM, FESEM, XRD, EDS, XPS, EIS, and potentiodynamic polarization. The extremely highest corrosion resistant coating was obtained when the cerium ion concentration in the plating bath was 16 mM. It has been observed that the presence of cerium ion in the plating bath led to changes in the morphology of the coating from pyramid nodular structure to coaxial structure. By adding cerium ion to the plating bath, a considerable grain refinement in the nanometer region was observed.

Inhibiting effect of cerium ions on corrosion of 3003 aluminum alloy in ethylene glycol–water solutions

In this study, the inhibiting effect of cerium ions (Ce3+) on corrosion of 3003 aluminum alloy (AA3003) in ethylene glycol–water solutions was investigated using a rotating cylinder electrode, simulating the hydrodynamic condition of the automotive cooling system. Electrochemical measurements and surface characterization were conducted to study the inhibiting mechanism of Ce3+ on the Al alloy corrosion. It is found that Ce3+ serves as a cathodic inhibitor, and inhibits effectively corrosion of AA3003 in the flowing ethylene glycol–water solutions. The inhibiting effect of Ce3+ is resulted from the formation and deposit of Ce oxide and/or Ce hydroxide on the electrode surface. With the immersion time, the Ce deposit layer increases its thickness to cover the second phase particles, eliminating the galvanic coupling effect between the second phase particles and Al alloy substrate.

Effect of cerium ion on the proliferation, differentiation and mineralization function of primary mouse osteoblasts in vitro

The effects of cerium ion (Ce 3+) on the proliferation, differentiation, adipocytic transdifferentiation and mineralization function of primary mouse osteoblasts (OBs) were investigated. The results indicated that Ce 3+ at all concentrations (1 × 10 −9, 1 × 10 −8, 1 × 10 −7, 1 × 10 −6, 1 × 10 −5, and 1 × 10 −4 mol/L) promoted the proliferation of osteoblasts (OBs). On day 1 and 3, Ce 3+ promoted the differentiation of OBs at concentrations of 1 × 10 −9, 1 × 10 −7, and 1 × 10 −6 mol/L, but inhibited the differentiation of OBs at higher concentrations. On day 2, Ce 3+ inhibited the differentiation of OBs at tested concentrations. On day 9 and 12, Ce 3+ inhibited the adipocytic transdifferentiation of OBs at most concentrations. On day 15, Ce 3+ promoted the adipocytic transdifferentiation of OBs at concentrations of 1 × 10 −9, 1 × 10 −6, 1 × 10 −5, and 1 × 10 −4 mol/L, but had no effects at other concentrations. Ce 3+ inhibited the formation of mineralized matrix nodules of OBs at concentrations of 1 × 10 −9, 1 × 10 −8 and 1 × 10 −7 mol/L, and promoted the formation of mineralized matrix nodules of OBs at other concentrations. These findings suggested that the effects of Ce 3+ on the proliferation, differentiation, adipocytic transdifferentiation and mineralization function of primary OBs depended on the concentration and culture time; moreover, they were pivotal factors for switching the biological effects of Ce 3+ from toxicity to activity, from damage to protection, or from down-regulation to up-regulation.

Effect of cerium ions on corrosion inhibition of PANI for iron in 0.5 M H2SO4

In recent years conducting polymers such as polyaniline are used as corrosion inhibitors for metals in acids. The performance of the inhibitor can be enhanced either by the addition of halide ions or metal cations. A study has been made on the effect of addition of ceric ions on the corrosion inhibition performance of polyaniline for iron in 0.5M H2SO4. Techniques such as electrochemical impedance spectroscopy, potentiodynamic polarization and linear polarization resistance methods have been employed to study the corrosion inhibition. The polyaniline has been used in the concentration range of 10–100ppm and the ceric ions concentration has been maintained at 1×10−3M. The inhibition efficiency of polyaniline at 10ppm has been increased from 53 to 88% and for 50ppm from 71 to 90% in the presence of ceric ions. The enhanced inhibition of polyaniline in presence of ceric ions is due to the higher coverage of polyaniline–cerium complex.

Effect of cerium ions in an arc peripheral plasma on the growth of radial single-walled carbon nanotubes

Radial single-walled carbon nanotubes (radial SWCNTs) are formed by using a direct current (dc) arc discharge when carbon and metal atoms are mixed in a gas phase after the vaporization and cooled together in a liquid droplet. Since SWCNTs sprout through the precipitation of saturated carbon atoms from liquid droplets during cooling, a mass synthesis of radial SWCNTs can be achieved when a large number of liquid droplets are generated. In order to understand the effects of arc peripheral plasma parameters (electrons, ions, radical atoms, and molecules) on the growth of radial SWCNTs, the optimum production efficiency of radial SWCNTs is investigated by superimposing a radio-frequency (rf) plasma on the thermal arc plasma and controlling the arc peripheral plasma density. Two parameters—the rf power and the dc potential—of the rf electrode, which is equipped above 20 mm from the center of an arc-discharge point, are changed with the constant He pressure (200 Torr), dc arc current (75 A), and power (2000 W). The production yield of radial SWCNTs is found to be enhanced under the condition of the rf power of 100 W and the dc component of the rf electrode voltage of −22V, revealing that the optimum ion flux and ion bombardment energy are important key parameters for the formation of radial SWCNTs.

Effect of Ce on NO direct decomposition in the absence/presence of O 2 over La 1− xCe xSrNiO 4 (0 ≤ x ≤ 0.3)

Effect of cerium ions on the activity of La 1− x Ce x SrNiO 4 (0 ≤ x ≤ 0.3) for NO decomposition was investigated both in the absence and presence of oxygen. The amount of Ce in the frame reached 30 at.% ( x = 0.3) in the present case without destroying the matrix structure. The Ce-substituted samples showed high activity for NO decomposition not only in the absence of O 2 but also in the presence of O 2, and the specific activity reached 1.59 μmol s −1 m −2 even 6.0%O 2 was fed to the reactant gas (La 0.7Ce 0.3SrNiO 4, T = 1123 K), indicating that the Ce addition can enhance the oxygen forbearance of catalyst. In addition, a new highly active site, which facilitates oxygen mobilization and desorption, might be formed in the sample due to the Ce addition, which thus resulted in the high activity for NO decomposition.