Room Temperature Synthesis of Nano Crystalline Cerium Oxide Using Hydrazine and Ammonia

Izu, Noriya; Itou, Toshio; Shin, Woosuck; Matsubara, Ichiro; Murayama, Norimitsu

doi:10.2109/jcersj.114.418

Cited by 9 publications

(7 citation statements)

References 10 publications

(12 reference statements)

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“…The self-assembly of such proto-crystalline structures could play a key role in the formation and growth of n-CeO 2 . Additionally, oxidation of Ce 3+ to Ce 4+ is promoted in a basic environment (Izu et al, 2006), and although the slow hydrolysis of HMT provides a controlled source of hydroxyl groups to sustain the oxidation and precipitation reactions, HMT is thought to play a more explicit role since this change in research papers 926 Andrew J. Allen et al USAXS study of nanocrystalline ceria Figure 7 (a) Principal particle volume fractions versus reaction time at 293, 298 and 308 K, with straight line fits giving growth rates of 1.59 (28), 2.59 (12) and 4.65 (63), respectively, all Â10 À5 % min À1 . (b) Arrhenius plot derived from (a), giving an activation energy for growth of the principal particle population of 49.1 (98) kJ mol À1 .…”

Section: Interpretation Of the Fine Feature Populationmentioning

confidence: 99%

In situultra-small-angle X-ray scattering study of the solution-mediated formation and growth of nanocrystalline ceria

et al. 2008

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Results are presented for an in situ synchrotron-based ultra-small-angle X-ray scattering (USAXS) study of the solution-mediated formation and growth of nanocrystalline ceria (n-CeO 2 ) using a new remote-controlled, isothermal, circulating fluid flow cell. The fluid flow mitigates or reduces X-ray beaminduced damage, air bubbles or particulate flocculation within the bulk solution, but prevents any coarse particulates that do form from settling out from suspension. Combined with the large-scale range accessible in USAXS studies, the flow cell has enabled measurement, in situ and in real time, of structural characteristics from 10 Å to a few micrometres in size as a function of the changing physical and chemical conditions. By applying a multi-component model, the nanoparticle formation and growth component has been identified. Control and online monitoring of flow rate, temperature and pH suspension conditions have permitted real-time studies of the formation and growth of the individual n-CeO 2 particles from homogeneous dilute solution over several hours. Aspects of the nanoparticle nucleation and growth are revealed that have not been observed directly in measurements on this system. research papers J. Appl. Cryst. (2008). 41, 918-929 Andrew J. Allen et al. USAXS study of nanocrystalline ceria 919 research papers J. Appl. Cryst. (2008). 41, 918-929 Andrew J. Allen et al. USAXS study of nanocrystalline ceria 921 research papers J. Appl. Cryst. (2008). 41, 918-929 Andrew J. Allen et al. USAXS study of nanocrystalline ceria 925 Figure 6Volume-weighted mean, median and mode diameters, and numberweighted mean diameter for the principal particle population versus reaction time at (a) 308 K, (b) 298 K and (c) 293 K. Capped vertical bars are the estimated standard deviation uncertainties. The lines are logarithmic fits to the data, plotted from the time that a discernible principal particle volume fraction can be detected.

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Section: Interpretation Of the Fine Feature Populationmentioning

confidence: 99%

In situultra-small-angle X-ray scattering study of the solution-mediated formation and growth of nanocrystalline ceria

et al. 2008

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“…X-ray diffraction ͑XRD͒ analysis showed the powders of CeO 2 and Ce 0.8 Zr 0.2 O 2 were single phase, respectively. 9 Scanning electron microscopy ͑SEM͒ observation showed the particle size of the powder obtained was about 200-300 nm. 9 The paste mixed with the obtained powder and organic binder ͑ethyl cellulose and terpineol͒ was screen printed on alumina sub-strate.…”

Section: Methodsmentioning

confidence: 97%

“…[3][4][5] We have researched and developed a resistive oxygen sensor using CeO 2 or CeO 2 -ZrO 2 . [6][7][8][9] Especially, we decreased the response time to several tens of milliseconds at 1073 K by decreasing the particle size of CeO 2 thick film. 10 It is important to investigate the influence of corrosion gas in exhaust gas on a resistive oxygen sensor for practical use.…”

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confidence: 97%

Influence of SO[sub 2] Gas on Output of Resistive Oxygen Sensors Using CeO[sub 2] and Ce[sub 0.8]Zr[sub 0.2]O[sub 2]

Izu

Shin

Matsubara

et al. 2005

J. Electrochem. Soc.

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The influence of SO 2 on the output of resistive oxygen sensors using CeO 2 and Ce 0.8 Zr 0.2 O 2 thick films was investigated. At 873 and 1073 K, the resistance of the sensors using CeO 2 film was strongly influenced by 1, 500 ppm SO 2 , and SO 2 caused a decrease of resistance. On the contrary, the resistance of the sensors using Ce 0.8 Zr 0.2 O 2 was hardly influenced. The resistivity of the reaction product, which was Ce 2 ͑SO 4 ͒ 3 , was 100 times greater than that of CeO 2 at 873 K. Thermodynamic calculation revealed that CeO 2 was more stable than Ce 2 ͑SO 4 ͒ 3 at 1073 K in 500 ppm SO 2 . These results showed that the resistance decrease of the sensor using CeO 2 film, caused by the introduction of SO 2 , was unrelated to the formation of the reaction product. It was believed that the resistance decrease of the sensor using CeO 2 film was due to the adsorption of electrically conductive substances on the CeO 2 surface. It was considered that the reason the influence of SO 2 on Ce 0.8 Zr 0.2 O 2 thick film was less than that on CeO 2 thick film was that the resistivity of Ce 0.8 Zr 0.2 O 2 was 1/10 times that of CeO 2 .The exhaust emission regulations for two-wheeled vehicles are becoming strict globally. In Japan, the amounts of HC and NO x will be restricted to 0.5 and 0.15 g/km, respectively. In order to reduce exhaust emissions, an oxygen gas sensor is indispensable. 1,2 A small sensor is required for two-wheeled vehicles because they do not have sufficient space. Resistive oxygen gas sensors have therefore become the focus of much attention, because they have a simple structure and it is easy to downsize them. 3-5 We have researched and developed a resistive oxygen sensor using CeO 2 or CeO 2 -ZrO 2 . 6-9 Especially, we decreased the response time to several tens of milliseconds at 1073 K by decreasing the particle size of CeO 2 thick film. 10 It is important to investigate the influence of corrosion gas in exhaust gas on a resistive oxygen sensor for practical use. 11 The influence of SO 2 on an oxygen sensor using CeO 2 thin film has been reported. 12 However, there is no report regarding the influence of SO 2 on oxygen gas sensors using CeO 2 thick film, and there is no report regarding the influence on oxygen sensors using CeO 2 -ZrO 2 thick or thin film.In this work, the influence of SO 2 on oxygen sensors using CeO 2 or Ce 0.8 Zr 0.2 O 2 thick films was investigated. Results showed that the influence of SO 2 was larger in the case of CeO 2 thick film compared with Ce 0.8 Zr 0.2 O 2 thick film. Furthermore, the reason the influence was larger in the case of CeO 2 thick film was also investigated. ExperimentalSensor fabrication.-The powder of oxide including cerium and zirconium ions was prepared as follows. The aqueous solutions of cerium nitrite and zirconium oxynitrate were mixed using a predetermined ratio ͑x Zr /͑x Zr + x Ce ͒: 0, 20 mol %͒, and the cation concentration of the resulting mixed aqueous solution was 0.010 mol/dm 3 . Next, mist of the mixed solution was introduced into a furnace ...

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“…In order to lower the sintering temperature of doped ceria, ultra-fine powders with nanometer size have been prepared by various precipitation methods using ammonia, 5),6) urea, 5) hydrazine hydrate, 6) oxalate, 7) and hexamethylenetetramine (HMT).…”

Section: )2)mentioning

confidence: 99%

Co-firing of LSM-GDC/GDC/NiO-GDC with addition of nano-GDC powder

Kubota

Ito

Kikuta

2008

J. Ceram. Soc. Japan

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Co-firing of a La0.8Sr0.2MnO3-δ (LSM)-gadolinium doped ceria(GDC)/GDC/NiO-GDC cell is investigated by the application of a mixed GDC powder. A fine starting GDC powder is synthesized by the homogeneous precipitation process, using hexamethylenetetramine (HMT), and mixed with a commercially available GDC powder. Shrinkage behavior of the chemically prepared, the commercial, and the mixed GDC powders is examined by thermo-mechanical analysis (TMA), which suggests that the mixed powder has good sinterability and compatible shrinkage with electrodes. A LSM-GDC/GDC/NiO-GDC cell prepared by lamination of electrode and electrolyte green sheets is co-fired at 1300°C for 4 h. The prepared fuel cell gives an output power density of 0.35 W/cm 2 at 600°C.

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Room Temperature Synthesis of Nano Crystalline Cerium Oxide Using Hydrazine and Ammonia

Cited by 9 publications

References 10 publications

In situultra-small-angle X-ray scattering study of the solution-mediated formation and growth of nanocrystalline ceria

In situultra-small-angle X-ray scattering study of the solution-mediated formation and growth of nanocrystalline ceria

Influence of SO[sub 2] Gas on Output of Resistive Oxygen Sensors Using CeO[sub 2] and Ce[sub 0.8]Zr[sub 0.2]O[sub 2]

Co-firing of LSM-GDC/GDC/NiO-GDC with addition of nano-GDC powder

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