Study on the Electronic Structure Control of Mn Oxide Nano-catalysts by Surface Functionalization

Redox-inactive Metal;Calcium Ion;Exchange Coupling;Zero-Field-Splitting;Manganese Oxide Nanoparticles;Ethylene Diamine Tetra Acetic acid(EDTA);620

공과대학 재료공학부 ;

University:서울대학교 대학원

关键词: Redox-inactive Metal;    Calcium Ion;    Exchange Coupling;    Zero-Field-Splitting;    Manganese Oxide Nanoparticles;    Ethylene Diamine Tetra Acetic acid(EDTA);    620;   

Others  :  http://s-space.snu.ac.kr/bitstream/10371/123377/1/000000133605.pdf

美国|英语

来源: Seoul National University Open Repository

【 摘 要 】

calcium ion and manganese ion are proposed to form pseudo-bridge as a major state and the nitrogen atoms are suggested to chelate the manganese ion on the surface of manganese oxide nanoparticles. Partially, some carboxylate groups of EDTA are considered to be bound as unidentate and bidentate mode as a mixture. Also, electronic structural analysis of calcium EDTA chelated manganese oxide nanoparticles was performed by EPR analysis. The calcium-affected manganese ions are verified to have high axial zero-field-splitting (D ~ 0.023 cm^-1) compared to conventional Mn (II) (D = 0.014 cm^-1) by a multi-frequency EPR simulation and are demonstrated to have weak exchange coupling between manganese ions (J below 1 cm^-1) via temperature dependency analysis of EPR and SQUID.The observation of electronic structural change of manganese, the axial distortion in the ligand field of manganese and weak exchange coupling between manganese ions, in this work will be a pioneering model in heterogeneous system for further application to catalysis and in the meantime for better understanding of the role of calcium ion in Mn-Ca cluster in nature.