Application of urea precipitation method in preparation of advanced ceramic powders

H, Qin; Tan, Xiaojian; Huang, Wuchao; Jiang, Jun; Jiang, Haochuan

doi:10.1016/j.ceramint.2015.06.032

Cited by 27 publications

(6 citation statements)

References 42 publications

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“…In the urea homogeneous precipitation method, which is widely used as a synthetic route for inorganic nanoparticles including cerium-containing materials, , a heating process is essential to achieve proper decomposition of the urea during the reaction. However, it is often difficult to control the temperature precisely for a long time and this could be an obstacle for the control of industrial-scale production of nanoparticles due to a thermal gradient inside the reactor that can lead to adverse consequences such as reduced particle uniformity .…”

Section: Resultsmentioning

confidence: 99%

Facile Room-Temperature Synthesis of Cerium Carbonate and Cerium Oxide Nano- and Microparticles Using 1,1′-Carbonyldiimidazole and Imidazole in a Nonaqueous Solvent

Choi

Kim

2021

ACS Omega

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Ceria nanoparticles (CeONPs) are versatile materials due to their unique catalytic properties, and cerium carbonate particles (CeCbPs) have been widely used as precursors for cerium oxide due to their ease of production. Urea is a widely used precipitant and a source of carbonate ions for the synthesis of CeONPs and CeCbPs, and the reaction temperature is important for controlling the rate of urea decomposition. However, the precise control of the temperature is often difficult, especially in large-scale reactions. Herein, we propose a homogeneous precipitation method that uses 1,1′-carbonyldiimidazole (CDI) and imidazole in acetone without heating. The decomposition rate of CDI can be controlled by the amount of water in the reaction mixture. In the synthesis of CeCbPs, unique particle morphologies of plate-, flying-saucer-, and macaron-like shapes and a wide range of sizes from 180 nm to 13 μm can be achieved by adjusting the amount of CDI, imidazole, and water in the reaction. These CeCbPs are transformed into ceria particles by calcination while maintaining their characteristic morphology. Moreover, the direct synthesis of 130 nm spherical CeONPs was possible by decreasing the amount of CDI in the reaction and the mixing time. These nanoparticles exhibited higher production efficiency and superior reactive oxygen species (ROS) scavenging properties compared to the other CeONPs obtained from calcination. These results demonstrate a novel method using CDI and imidazole in the synthesis of CeONPs and CeCbPs without the aid of a heating process, which may be useful in the large-scale synthesis and application of CeO nanomaterials.

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Section: Resultsmentioning

confidence: 99%

Facile Room-Temperature Synthesis of Cerium Carbonate and Cerium Oxide Nano- and Microparticles Using 1,1′-Carbonyldiimidazole and Imidazole in a Nonaqueous Solvent

Choi

Kim

2021

ACS Omega

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“…Solvent EG plays an important role in decreasing the agglomeration degree and improving the size uni- [27]. To date, even though numerous literatures about urea decomposition in aqueous solution are available, few reports are about urea decomposition performance in EG medium [8,9,11,28]. In our study, the crystal water in MgCl 2 •6H 2 O supplies the precursor nucleation condition (stage a and b in Fig.…”

Section: Formation Mechanismmentioning

confidence: 87%

Roles of ethylene glycol solvent and polymers in preparing uniformly distributed MgO nanoparticles

Hai¹,

Zhou³

et al. 2017

Journal of Asian Ceramic Societies

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This study focus on specifying the roles of solvent ethylene glycol (EG) and polymers for synthesis of uniformly distributed magnesium oxide (MgO) nanoparticles with average crystallite size of around 50 nm through a modified polyol method. Based on different characterization results, it was concluded that, Mg 2+ ions was precipitated by the −OH and CO 3 2− ions decomposed from urea in ethylene glycol (EG) medium (CO(NH 2) 2 → NH 3 + HNCO, HNCO + H 2 O → NH 3 + CO 2), thus forming well crystallized Mg 5 (CO 3) 4 (OH) 2 (H 2 O) 4 precursor which could be converted to MgO by calcination. Surface protectors PEG and PVP have no obvious influences on cyrtsal structure, morphology and size uniformity of asprepared precursors and target MgO nanoparticles. In comparison with polymers PEG and PVP, solvent EG plays an important role in controlling the morphology and diameter uniformity of MgO nanoparticles.

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“…However, the precipitation of solid phases from urea solutions is a rather complex phenomenon; small variations of precipitation parameters such as the initial cation concentration, aging time and temperature produce dramatic changes in the chemical stoichiometry, crystal structure, size distribution and particle morphology of the precipitated solids. [23][24][25][26] Therefore, before the GDC10 infiltration, an additional experiment was carried out to optimize the urea precipitation method.…”

Section: Resultsmentioning

confidence: 99%

The Electrochemical Properties of Nanocrystalline Gd_0.1Ce_0.9O_1.95Infiltrated Solid Oxide Co-Electrolysis Cells

Hong

Balamurugan

et al. 2018

J. Electrochem. Soc.

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Ni-YSZ/YSZ/GDC/LSCF6428-GDC10 solid oxide cells were fabricated and investigated in high-temperature H 2 O/CO 2 co-electrolysis using various inlet fuel compositions at 800 • C. Furthermore, to see the effect of infiltration on co-electrolysis, the precursor solution for a 10% gadolinium-doped ceria (GDC10) catalyst was dispersed into a fuel electrode backbone by a controlled urea/cation infiltration method. The influence of the inlet gas composition on the syngas product ratio was investigated by in-line gas chromatography. To understand the high-temperature H 2 O/CO 2 co-electrolysis cell performance, electrochemical impedance spectroscopy (EIS) under open-circuit voltage and I-V characteristics, by the electrochemical reactions occurring at the electrodes of prepared solid oxide electrolysis cell (SOEC) were examined. When the inlet gas composition was N 2 63.5%, H 2 5%, CO 2 11.5% and H 2 O 20% under electrolysis current density at −0.6 A cm −2 , the H 2 /CO ratio of infiltrated cell was improved from 2.1 to 2.8 compared with the non-infiltrated cell. The thermodynamic factors determining the size, morphology and shape of the infiltrated particles were discussed. Compared to various dissociative methods for syngas generation such as coal gasification and natural gas reforming, high-temperature CO 2 and H 2 O co-electrolysis is a promising alternative for the generation of syngas and CO 2 utilization due to its high efficiency and flexibility.1-3 When coupled with clean energies, such as wind, solar and nuclear energies, high-temperature H 2 O/CO 2 co-electrolysis can play a crucial role in future energy strategies based on its chemical transformation to a highly valuable product. 4,5 In particular, the direct syngas production carried out through high-temperature solid oxide electrolysis cells (SOECs) seems to be strong candidates because of low internal resistance that allows high reaction rates at low voltage via efficient use of heat and electricity. [6][7][8][9] By inletting H 2 O and CO 2 as a fuel, SOECs can generate chemical energy in the form of a syngas, which can be further converted into valuable liquid fuels such as synthetic diesel or dimethyl ether through a catalytic process, [10][11][12] thereby resolving fuel-related supply-and-demand issues as well as greenhouse gas emissions.13,14 Considerable attention was paid to improve the high-temperature SOEC conversion efficiency for large scale clean-energy applications. Carl M. Stoots 15 at the Idaho National Laboratory developed a large-scale high-temperature H 2 O/CO 2 co-electrolysis model and predicted an overall syngas production of up to 49%. However, the development of efficient H 2 O/CO 2 coelectrolysis SOECs is still a critical challenge, since it is a more complicated process compared to pure H 2 O or CO 2 electrolysis involved in the different reactions that compete in the final syngas formation. Since the final syngas compositions' controlling mechanism depends on the kinetics of multiple reactions, the formation of CO occurs typically...

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Application of urea precipitation method in preparation of advanced ceramic powders

Cited by 27 publications

References 42 publications

Facile Room-Temperature Synthesis of Cerium Carbonate and Cerium Oxide Nano- and Microparticles Using 1,1′-Carbonyldiimidazole and Imidazole in a Nonaqueous Solvent

Facile Room-Temperature Synthesis of Cerium Carbonate and Cerium Oxide Nano- and Microparticles Using 1,1′-Carbonyldiimidazole and Imidazole in a Nonaqueous Solvent

Roles of ethylene glycol solvent and polymers in preparing uniformly distributed MgO nanoparticles

The Electrochemical Properties of Nanocrystalline Gd_0.1Ce_0.9O_1.95Infiltrated Solid Oxide Co-Electrolysis Cells

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Application of urea precipitation method in preparation of advanced ceramic powders

Cited by 27 publications

References 42 publications

Facile Room-Temperature Synthesis of Cerium Carbonate and Cerium Oxide Nano- and Microparticles Using 1,1′-Carbonyldiimidazole and Imidazole in a Nonaqueous Solvent

Facile Room-Temperature Synthesis of Cerium Carbonate and Cerium Oxide Nano- and Microparticles Using 1,1′-Carbonyldiimidazole and Imidazole in a Nonaqueous Solvent

Roles of ethylene glycol solvent and polymers in preparing uniformly distributed MgO nanoparticles

The Electrochemical Properties of Nanocrystalline Gd0.1Ce0.9O1.95Infiltrated Solid Oxide Co-Electrolysis Cells

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The Electrochemical Properties of Nanocrystalline Gd_0.1Ce_0.9O_1.95Infiltrated Solid Oxide Co-Electrolysis Cells