Jang-Hoon Chung

New Group 9 metal complexes containing N,P-chelate ligand system.: Synthesis, characterization and application to catalytic hydrogenation

Abstract New N , P -chelating o -carboranylaminophosphine ligand Cab N , P 2 [Cab N , P = o -C 2 B 10 H 10 (CH 2 NMe 2 )(PPh 2 )- N , P ] was prepared from o -carboranylamine LiCab N [Cab N = o -C 2 B 10 H 10 (CH 2 NMe 2 )- N ] and chlorodiphenylphosphine. Consequently, the reaction of [M(cod)(solv) 2 ] + BF 4 − (M=Rh, Ir; cod=cycloocta-1,5-diene) with 2 was investigated. The resulting rhodium and iridium metal complexes [(Cab N , P )M(cod)] + BF 4 − 3 (M=Rh 3a , Ir 3b ) were characterized by NMR spectroscopy and elemental analysis. In addition, an X-ray structure analysis was performed on complex 3a , where the potential N , P -chelate ligand 2 was found to coordinate in a bidentate mode. The subsequent reaction of 3 with PPh 3 and CO resulted in the dissociation of the N , P -chelate ligand 2 to yield the penta-coordinate metal complexes [(PPh 3 ) 2 M(CO) 3 ] + BF 4 − 4 (M=Rh 4a , Ir 4b ). The structure of 4a was determined by X-ray diffraction analysis, exhibiting a trigonal bipyramidal configuration with the triphenylphosphine ligands occupying axial positions. The activities of complex 3 as a catalyst precursor during the hydrogenation of cyclohexene were tested and produced the cyclohexane with 100% conversion in the case of 3a .

Study on ZrO2:Er Thin Films Fabricated by Metal-Organic Chemical Vapor Deposition

ZrO2:Er thin films for active waveguide applications were fabricated by the metal-organic chemical vapor deposition (MOCVD) method. X-ray diffraction demonstrated that there is a rapid change of preferred orientation, from (001) to (100), in samples of which the Er contents are 2.39 mol% and 10.41 mol%, respectively. The observed phase change from monoclinic to tetragonal was attributed to the c/a ratio reduction with Er ion incorporation into the ZrO2 matrix. A considerable increase in oxygen deficiency leads to the phase change, as revealed by X-ray photoelectron spectroscopy (XPS). The near-infrared photoluminescence of 4I13/2 → 4I15/2 transition was investigated and the quenching concentration for the luminescence was found to be 2.39 mol%. It was proposed that the oxygen deficiency observed at 10.41 mol% Er concentration is mainly responsible for the quenching phenomenon.

Synthesis and Characterization of Covalently Cross-Linked SPEEK/Cs-substituted MoSiA/Ceria Composite Membranes with MoSiA for Water Electrolysis

>> 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 μL. Cs-MoSiA was added to increase proton conductivity. Ceria (CeO2) 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°C which was better than Nafion 117 membrane.

Study of Characteristic of Covalent Cross-linked SPEEK/Silane 4wt%/Cs-substituted MoPA/Ceria hybrid Membrane for Water Electrolysis

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 ket one (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). Co nsequently, 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 , 55.50 MPa of tensile strength and 4.37% of breeding out of MoPA. Ai

The Preparation and Characteristics of Covalently Cross-Linked SPEEK/Cs-TPA/Ceria Composite Membranes for Water Electrolysis

Abstract >> Ceria (CeO 2 ) was used to scavenge free radicals which attack the membrane in the polymer electrolytemembrane 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 sulfonatedpolyether 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 methodwith loading the highly dispersed ceria and cesium-substituted tungstophosphoric acid (Cs-TPA) with cross-linkingagent 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℃, 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. Key words : Ceria(Cerium(IV) oxide, 세리아), SPEEK(술폰화 폴리에테르에테르케톤), PEMWE(고분자 전해질막 수전해), Covalently cross-link(공유가교결합), Cs-TPA(Cs-substituted TPA), Oxidative stability(산화내구성), Radical scavenger(라디칼 스캐빈져)

Research of Characterization of Covalently Cross-linked SPEEK/Cs-Substituted MoPA/Ceria 1wt% Composite Membrane for Water Electrolysis

Ceria () 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/-MoPA/ceria(1%) membrane showed the optimum results such as 0.1095S/cm of proton conductivity at , 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.

The Synthesis and Characteristics of Covalently Cross-Linked SPEEK/Cs-substituted TPA/CeO 2 Composite Membranes for PEMWE

CL-SPEEK/Cs-TPA/CeO2 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 (CeO2) was used to scavenge free radicals which attack the membrane in the PEMWE circumstance and to increase the duration of the membrane. In conclusion, CL-SPEEK/Cs(1)-TPA/Ceria 1% membrane showed the optimum results such as 0.119 S/cm at 80°C of proton conductivity and 62MPa of tensile strength.