• Korean Chemical Engineering Research
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• 제46권6호
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• pp.1029-1038
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• 2008

전이금속 산화물의 전구체가 들어있는 합성모액을 수열 반응시켜 전이금속 산화물이 고정된 하이드로탈사이트를 제조하여 이들에 대한 이산화질소의 흡착 성질을 조사하였다. 전이금속 산화물의 분산도, 이산화질소의 흡착량 및 흡착상태를 XRD, SEM, XPS, 질소 흡착등온선, 중량식 흡착법, FT-IR, 승온탈착법으로 조사하였다. 전이금속 산화물은 주로 하이드로탈사이트의 표면에 분산 담지되었으며, 철과 니켈 산화물이 고정된 하이드로탈사이트에 이산화질소가 많이 흡장되었다. 철 산화물이 표면에 분산되어 담지되면 이산화질소의 흡장량이 많지만, 철 산화물이 지나치게 많이 담지되면 덩어리져서 표면의 염기점을 차폐하므로 이산화질소의 흡장량이 오히려 줄어들었다. 철 산화물의 고정량이 적절하면 하이드로탈사이트에서 이산화질소의 흡장세기는 약해지지만, 흡장량은 많아지고 수열 안정성이 증진되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2028-2030
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• 2005

The electrical conductivity of manganese oxide and complex manganese oxide produced by anodic deposition method was measured. The additive transition metal is Cu, Co and Fe. The transition metals like as Cu, Co and Fe improved electrical conductivity of complex manganese oxide compared with manganese oxide. This is coincide with the results of molecular orbital calculation by DV-Xa.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.303.2-303.2
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• 2014

The oxides of group IV transition metals such as titanium, zirconium, hafnium have many important current and future application, including protective coatings, sensors and dielectric layers in thin film electroluminescent (TFEL) devices. Recently, group IV transition metal oxide films have been intensively investigated as replacements for SiO2. Due to high permittivities (k~14-25) compared with SiO2 (k~3.9), large band-gaps, large band offsets and high thermodynamic stability on silicon. Herein, we report the synthesis of new group IV transition metal complexes as useful precursors to deposit their oxide thin films using chemical vapor deposition technique. The complexes were characterized by FT-IR, 1H NMR, 13C NMR and thermogravimetric analysis (TGA). Newly synthesised compounds show high volatility and thermal stability, so we are trying to deposit metal oxide thin films using the complexes by Atomic Layer Deposition (ALD).

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3183-3189
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• 2010

In order to increase the specific capacitance and energy density of supercapacitors, non-aqueous supercapacitors were prepared using lithium transition-metal oxides and activated carbons as active materials. The electrochemical properties were analyzed in terms of the content of lithium transition-metal oxides. The results of cyclic voltammetry and AC-impedance analyses showed that the pseudocapacitance may stem from the synergistic contributions of capacitive and faradic effects; the former is due to the electric double layer which is prepared in the interface of activated carbon and organic electrolyte, and the latter is due to the intercalation of lithium ($Li^+$) ions. The specific capacitance and energy density of a supercapacitor improved as the lithium transition-metal oxides content increased, showing 60% increase compared to those of supercapacitor using a pure activated carbon positive electrode.

• 한국수소및신에너지학회논문집
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• 제21권2호
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• pp.81-88
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• 2010

Hydrogen energy applications have recognized clean materials and high energy carrier. Accordingly, Hydrogen energy applies for fuel cell by Mg and Mg-based materials. Mg and Mg-based materials are lightweight and low cost materials with high hydrogen storage capacity. However, commercial applications of the Mg hydride are currently hinder by its high absorption/desorption temperature, and very slow reaction kinetics. Therefore one of the most methods to improve kinetics focused on addition transition metal oxide. Addition to transition metal oxide in $MgH_x$ powder produce $MgH_x$-metal oxide composition by mechanical alloy and it analyze XRD, EDS, TG/DSC, SEM, and PCT. This report considers kinetics by transition metal oxide rate and Hydrogen pressure. In this research, we can see behavior of hydriding/dehydriding profiles by addition catalyst (transition metal oxide). Results of PCI make a excellent showing $MgH_x$-5wt.% Sc2O3 at 623K, $MgH_x$-10wt.% $Sc_2O_3$ at 573K.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.87-88
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• 2012

Metal oxide nanostructures have been applied to various fields such as energy, catalysts and electronics. We have freely designed one and two-dimensional (1 and 2-D) metal (transition metals and lanthanides) oxide nanostructures, characterized them using various techniques including scanning electron microscopy, transmission electron microscopy, X-ray diffraction crystallography, thermogravimetric analysis, FT-IR, UV-visible-NIR absorption, Raman, photoluminescence, X-ray photoelectron spectroscopy, and temperature-programmed thermal desorption (reaction) mass spectrometry. In addition, Ag- and Au-doped metal oxides will be discussed in this talk.

• 한국세라믹학회지
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• 제54권1호
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• pp.1-8
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• 2017

Electrochemical water splitting to produce hydrogen energy is regarded as a promising energy conversion process for its environmentally friendly nature. To improve cell efficiency, the development of efficient water oxidation catalysts is essentially demanded. For several decades, 3d transition metal oxides have been intensively investigated for their high activity, good durability and low-cost. This review covers i) recent progress on 3d transition metal oxide electrocatalysts and ii) the reaction mechanism of oxygen evolving catalysis, specifically focused on the proposed pathways for the O-O bond formation step.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 하계학술연구발표회 및 한.일 공동심포지엄
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• pp.17-17
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• 2003

Semiconductors with ferromagnetism at room temperature has been actively searched for in recent years; a prospect of devices using both charge and spin continuously gives impetus to the activities. Transition metal doped oxide materials have been of particular interest. Co substituted ZnO [1] and TiO$_2$ [2] thin films, for example, were reported to show ferromagnetic properties at room temperature. However, various studies do not seem to converge on a definite picture [3,4,5]. The issue is rather fundamental: whether a system shows ferromagnetic properties at all, and in case it does, whether the system possesses a close coupling between magnetism and transport properties. In this talk, we shall assess the current status of transition metal doped oxide materials as room temperature ferromagnetic semiconductors.

• Applied Science and Convergence Technology
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• 제23권6호
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• pp.317-327
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• 2014

In order to develop nano-devices with much lower power consumption for beyond-CMOS applications, the fundamental understanding and precise control of the electronic properties of ultrathin transition metal oxide (TMO) films are strongly required. The metal-insulator transition (MIT) is not only an important issue in solid state physics, but also a useful phenomenon for device applications like switching or memory devices. For potential use in such application, the electronic structures of MIT, observed for TMO nano-structures, have been investigated using a synchrotron radiation angle-resolved photoelectron spectroscopy system combined with a laser molecular beam epitaxy chamber and a scanning photoelectron microscopy system with 70 nm spatial resolution. In this review article, electronic structures revealed by soft X-ray nano-spectroscopy are presented for i) polarity-dependent MIT and thickness-dependent MIT of TMO ultrathin films of $LaAlO_3/SrTiO_3$ and $SrVO_3/SrTiO_3$, respectively, and ii) electric field-induced MIT of TMO nano-structures showing resistance switching behaviors due to interfacial redox reactions and/or filamentary path formation. These electronic structures have been successfully correlated with the electrical properties of nano-structured films and nano-devices.

• Corrosion Science and Technology
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• 제14권6호
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• pp.301-312
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• 2015

Corrosion of zirconium fuel cladding is known to limit the lifetime and reloading cycles of fuel in nuclear reactors. Oxide layers formed on ZIRLO4^{TM}$ cladding samples, after immersion for 300-hour and 50-day in a simulated primary water chemistry condition ($360^{\circ}C$ and 20 MPa), were analyzed by using the scanning transmission electron microscopy (STEM), in-situ transmission electron microscopy (in-situ TEM) with the focused ion beam (FIB) technique, and X-ray diffraction (XRD). Both samples (immersion for 300 hours and 50 days) revealed the presence of the ZrO sub-oxide phase at the metal/oxide interface and columnar grains developed perpendicularly to the metal/oxide interface. Voids and micro-cracks were also detected near the water/oxide interface, while relatively large lateral cracks were found just above the less advanced metal/oxide interface. Equiaxed grains were mainly observed near the water/oxide interface.