• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.2
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• pp.101-107
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• 2013

Cerium compounds such as Cerium hydroxide ($Ce(OH)_3$), Cerium chloride ($CeCl_3{\cdot}nH_2O$), Cerium carbonate hydrate ($Ce_2(CO_3)_3{\cdot}8H_2O$), Cerium oxide ($CeO_2$) were synthesized using recycled Ce precursor. Cerium(IV) oxide of nanoparticles were obtained by Ultra-sonication. Cerium-sodium- sulfate compound was synthesized through acid-leaching and addition of sodium sulfate from 99 wt% purity of Ce precursor as a starting material that was recycled from the waste polishing slurry. Moreover Cerium hydroxide was obtained from Cerium-sodium-sulfate compound by adding to sodium hydroxide solution. Then Cerium chloride was synthesized by adding of hydrochloric acid to Cerium hydroxide. Needle-shaped Cerium carbonate hydrate was synthesized in the continuous process and Cerium(IV) oxide with 30~40 nm size was subsequently obtained by the calcinations and dispersion.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.866-871
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• 1997

The com starch was treated with propylene oxide, 1,2-epoxybutane, glycidyl methacrylate, maleic anhydride, caprolactone, respectively, in order to alter the hydrophilicity and the reactivity of starch. When the starch was not dried, poor reaction was observed except the reaction with propylene oxide or maleic anhydride. The treated starches were grafted with styrene by several different polymerization methods. Solution polymerization and redox polymerization using cerium(IV) ion show poor grafting efficiency and poor yield. Encapsulation of starch with polystyrene by suspension polymerization was difficult due to the hydrophilicity of the starch. Among the examined methods, emulsion polymerization was found to be the suitable way to graft styrene onto starch.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.6
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• pp.524-531
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• 2015

To improve the electrochemical and mechanical characteristics, engineering plastic of the sulfonated polyether ether ketone (SPEEK) as polymer matrix was prepared in the sulfonation reaction of polyether ether ketone (PEEK). The SPEEK organic-inorganic blended composite membranes were prepared by sol-gel casting method. It was loaded with the highly dispersed ceria and cesium-substituted molybdosilicic acid (Cs-MoSiA) and 1,4-diiodobutane which was cross-linking agent contents of $10{\mu}L$. Cs-MoSiA was added to increase proton conductivity. Ceria ($CeO_2$) was used as a free radical scavenger which degrade the membrane in polymer electrolyte membrane water elctrolysis (PEMWE). In conclusion, CL-SPEEK/Cs-MoSiA/Ceria 1% composite membrane showed high proton conductivity 0.2104 S/cm at $25^{\circ}C$ which was better than Nafion 117 membrane.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.6
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• pp.561-569
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• 2014

Ceria ($CeO_2$) was used to increase the durability of the membrane in the polymer electrolyte membrane water electrolysis (PEMWE) circumstance. The sulfonated polyether ether ketone (SPEEK) as polymer matrix was prepared in the sulfonation reaction of polyether ether ketone (PEEK) to improve electrochemical characteristics. After sulfonation reaction, the organic-inorganic blended composite membranes were prepared by means of sol-gel casting method with loading the highly dispersed $CeO_2$ and Cs-substituted molybdophosphoric acid (Cs-MoPA) with cross-linking agent (tetrapropyl orthosilicate). Consequently, the composite membrane CL-SPEEK/Silane 4wt%/Cs-MoPA/Ceria(1%) showed the improved characteristics such as 82% of water content, 0.11136 S/cm of proton conductivity at $80^{\circ}C$, 55.50 MPa of tensile strength and 4.37% of breeding out of MoPA.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.3
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• pp.212-220
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• 2015

The engineering plastic of sulfonated polyether ether ketone (SPEEK) as a polymer matrix has been developed in this lab to replace Nafion, solid polymer electrolytes of perfluorosulfonic acid membrane which has several flaws such as high cost, and limited operational temperature above $80^{\circ}C$. The SPEEK was prepared in the sulfonation reaction of polyether ether ketone (PEEK). The organic-inorganic blended composite membranes were prepared by sol-gel casting method with loading the highly dispersed ceria and cesium-substituted tungstosilicic acid (Cs-TSiA) with cross-linking agent contents of 0.01 mL. In conclusion, CL-SPEEK/Cs-TSiA/ceria 1% membrane showed the optimum results such as 0.1882 S/cm of proton conductivity at $80^{\circ}C$, and 99.61 MPa of tensile strength which were better than Nafion 117 membrane.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.2
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• pp.151-160
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• 2014

CL-SPEEK/Cs-TPA/$CeO_2$ composite membrane was prepared for polymer electrolyte membrane water electrolysis (PEMWE). In order to improve the electrochemical, mechanical, durabilities and electrocatalytic characteristics, engineering plastic of polyether ether ketone (PEEK) as polymer matrix was sulfonated and the organic-inorganic blend composite membranes was prepared by loading cesium-substituted tungstophosphoric acid (Cs-TPA) by titration method with cross-linking agent contents of 0.01mL. Ceria ($CeO_2$) was used to scavenge free radicals which attack the membrane in the PEMWE circumstance and to increase the duration of the membrane. CL-SPEEK/$Cs_{(1)}$-TPA/CeriaIn conclusion, 1% membrane showed the optimum results such as 0.119 S/cm at $80^{\circ}C$ of proton conductivity and 62MPa of tensile strength.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.1
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• pp.1-10
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• 2014

Ceria ($CeO_2$) was used to scavenge free radicals which attack the membrane in the polymer electrolyte membrane water electrolysis (PEMWE) circumstance and to increase the duration of the membrane. In order to improve the electrochemical, mechanical and electrocatalytic characteristics, engineering plastic of the sulfonated polyether ether ketone (SPEEK) as polymer matrix was prepared in the sulfonation reaction of polyether ether ketone (PEEK) and the organic-inorganic blended composite membranes were prepared by sol-gel casting method with loading the highly dispersed ceria and cesium-substituted phophomolybdic acid(Cs-MoPA) with cross-linking agent contents of 0.01mL. In conclusion, CL-SPEEK/$Cs_{(2.5)}$-MoPA/ceria(1%) membrane showed the optimum results such as 0.1095S/cm of proton conductivity at $80^{\circ}C$, 2.906meq./g-dry-membrane of ion exchange capacity and mechanical characteristics, and 49.73MPa of tensile strength which were better than Nafion 117 membrane.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.5
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• pp.437-447
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• 2012

Ceria ($CeO_2$) was used to scavenge free radicals which attack the membrane in the polymer electrolyte membrane water electrolysis (PEMWE) circumstance and to increase the duration of the membrane. In order to improve the electrochemical, mechanical and electrocatalytic characteristics, engineering plastic of the sulfonated polyether ether ketone (SPEEK) as polymer matrix was prepared in the sulfonation reaction of polyether ether ketone (PEEK) and the organic-inorganic blended composite membranes were prepared by sol-gel casting method with loading the highly dispersed ceria and cesium-substituted tungstophosphoric acid (Cs-TPA) with cross-linking agent contents of 0.01 mL. In conclusion, CL-SPEEK/Cs-TPA/ceria (1%) membrane showed the optimum results such as 0.130 S/cm of proton conductivity at $80^{\circ}C$, 2.324 meq./g-dry-membrane of ion exchange capacity and mechanical characteristics, and 65.03 MPa of tensile strength which were better than Nafion 117 membrane.