• Bulletin of the Korean Chemical Society
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• 제18권10호
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• pp.1082-1085
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• 1997

The Near-Edge X-ray Absorption Fine Structure (NEXAFS) technique and Differential Scanning Calorimetry (DSC) were utilized to investigate the reaction of CH4 and O2 on the MoO3/SiO2 catalyst. The NEXAFS results showed that the stoichiometry of the molybdenum oxide catalyst supported on silica was MoO3. MoO3 was reduced to MoO2 when the catalyst was exposed to CH4 at 773 K. NEXAFS results confirm that lattice oxygen is directly related to the process of CH4 oxidation which takes place on the surface of MoO3/SiO2 catalysts. DSC results show that the structure of MoO3 changes around 573 K and this structural change seems to improve the migration of oxygen in the lattice.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제26회 추계학술대회
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• pp.93-99
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• 1997

High Temperature wear behavior of plasma sprayed ZrO$_2$ and MoS$_2$, $Fe_2O_3$ coatings were investigated for high temperature wear resistance applications. The MoS$_2$, $Fe_2O_3$ added powders containing 2.5, 5.0, 7.5, 10.0 mol% of $MoS_2$, $Fe_2O_3$ for plasma spray were made by spray drying method. Wear test were performed at temperature ranges from room temperature to 600$\circ$C. The microstructural change of coatings and the worn. surface were examined by SEM and XRD. In ZrO$_2$ coating, the coefficient of friction and wear amount of room temperature to 400$\circ$C was increased with temperature and decreased with temperature over 400$\circ$C. The coefficient of friction and wear amount of MoS$_2$ added coatings were increased with temperature, but those of $Fe_2O_3$ added coatings had lower coefficient of friction and higher wear resistance than ZrO$_2$ coating.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2004년도 추계학술대회
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• pp.277-279
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• 2004

$300^{\circ}C$ 소성 Pt/MoO3가 수소를 흡착후 탈착하는 속도를 측정하였다. 두가지 흡착 속도를 나타내는 Pt/MoO3 촉매에서 탈착량은 흡착량과 탈착 온도의 증가에 비례하는 것을 알 수 있었다. 또한 X-Ray Photoelectron Spectroscope(XPS) 결과로부터 Pt와 MoO3간의 활성점에 존재하는 Cl의 존재가 수소 이동 속도를 결정하는 것으로 판단되었다.

• 대한화학회지
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• 제26권2호
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• pp.81-87
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• 1982

한 개 산소 가교 이핵몰리브덴 (V) 착물, $Mo_2O_3(NCS)_4(Bipy)_2\;(Bipy = bipyridine),\;Mo_2O_3(NCS)_4(Phen)_2$ (Phen = 1,10-phenanthroline), 및 $Mo_2O_3(NCS)_4(Ox)_2(OxH)_2 $(Ox = oxinato and OxH = oxine)이 합성되었다. 그들의 전자 및 적외선 스펙트라, 전기 전도도, 그리고 자화율을 측정하였다. 그 결과 이들 착물은 모두 전기적으로 중성이며 약 0.5BM 정도의 자기 모멘트를 가진 이량체였다. 그리고 oxine 착물, $Mo_2O_3(NCS)_2(Ox)_2(OxH)_2$에서 oxine은 일부는 한 자리 리간드로, 일부는 두 자리 리간드로 결합하고 있는 듯 하다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.460-463
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• 2002

$MoO_3$ thin films were deposited on electrode and heater screen-printed alumina substrates in $O_2$ atmosphere by RF reactive sputtering using Molybdenum metal target. The deposition was performed at $300^{\circ}C$ with 350W of a forward power in an $Ar-O_2$ atmosphere. The working pressure was maintained at $3{\times}10^{-2}mtorr$ and all deposited films were annealed at $500^{\circ}C$ for 5hours. To investigate gas sensing characteristics of the addition doped $MoO_3$ thin film, Co, Ni and Pt were used as adding dopants. The sensing properties were investigated in tenn of gas concentration under exposure of reducing gases such as $H_2$, $NH_3$ and CO at optimum working temperature. Co-doped $MoO_3$ thin film shows the maximum 46.8% of sensitivity in $NH_3$ and Ni-doped $MoO_3$ thin film exhibits 49.7% of sensitivity in $H_2$.

• 한국전기전자재료학회논문지
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• 제16권8호
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• pp.705-710
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• 2003

MoO$_3$thin films were deposited on electrode of alumina substrates in $O_2$atmosphere by RF reactive sputtering using molybdenum metal target. The deposition was performed at 30$0^{\circ}C$ with 350 W of a forward power in an Ar-O$_2$atmosphere. The working pressure was maintained at 3$\times$10$^{-2}$ torr and all deposited films were annealed at 50$0^{\circ}C$ for 5 hours. The surface morphology of films was observed by using a SEM and crystalline phases were analyzed by using a XRD. To investigate gas sensing characteristics of the doped MoO$_3$thin film, Co, Ni and Pt were used as dopants. The sensing properties were investigated in term of gas concentration under exposure of reducing gases such as H$_2$, NH$_3$and CO at optimum working temperature. Co-doped MoO3 thin film shows the maximum 46.8 % of sensitivity in NH$_3$ and Ni-doped MoO$_3$thin film exhibits 49.7 % of sensitivity in H$_2$.

• 센서학회지
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• 제24권3호
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• pp.151-154
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• 2015

The gas sensing characteristic of $MoS_2-MoO_2$ composite yolk-shell spheres were investigated. $MoO_3$-carbon composite spheres were prepared by ultrasonic spray pyrolysis of aqueous droplets containing Mo-source and sucrose in nitrogen, which were converted into $MoO_3$ yolk-shell spheres by heat treatment at $400^{\circ}C$ in air. Subsequently, $MoS_2-MoO_2$ composite yolk-shell spheres were prepared by the partial sulfidation of $MoO_3$. The $MoS_2-MoO_2$ composite yolk-shell spheres showed relatively low and irreversible gas sensing characteristics at < $200^{\circ}C$. In contrast, the sensor showed high and reversible response (S=resistance ratio) to 5 ppm $NO_2$ (S=14.8) at $250^{\circ}C$ with low cross-responses (S=1.17-2.13) to other interference gases such as ethanol, CO, xylene, toluene, trimethylamine, $NH_3$, $H_2$, and HCHO. The $MoS_2-MoO_2$ composite yolk-shell spheres can be used as reliable sensors to detect $NO_2$ in a selective manner.

• 한국산학기술학회논문지
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• 제5권6호
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• pp.558-561
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• 2004

암모늄헵타몰리브데이트(ammonium heptamolybdate, AHM)를 전구체로 제조한 실리카 담지 몰리브드늄$(MoO_{3}/SiO_{2})$ 촉매의 구조적 특성을 x-ray 회절기(XRD)를 사용하여 자세히 고찰하였다. 몰리브드늄의 표면담지량은 0.2부터 4.0 atoms $Mo/nm^{2}$로 변화하였으며, 담지촉매의 소성온도는 $300\~500^{\circ}C$로 변화하여 열역학적으로 형성 가능한 모든 몰리브드늄산화물의 구조를 고찰하였다. 담지량이 큰 경우(4 atoms $Mo/nm^{2}$), $300^{\circ}C$소성에서는 뭉쳐있거나 잘 분산된 hexagonal 형태의 결정체가 형성되었으며, $500^{\circ}C$로 소성온도를 증가하면 뭉친 orthorhombic 형태의 $MoO_{3}$ 결정체가 형성되었다. 뭉친 orthorhombic 형태의 결정체는 담지량이 1.1 atom $Mo/nm^{2}$이상이 되면 형성된 반면 잘 분산된 hexagonal 형태의 결정체는 가장 큰 표면 담지량 4.0 atoms $Mo/nm^{2}$에서도 고찰하기가 어려웠다. 이러한 hexagonal 결정체의 담체 표면에서의 높은 분산은 암모니아로 인한 몰리브드늄 산화물($MoO_{3}$)과 실리카($SiO_{2}$) 담체 사이의 강한 표면작용에 기인한 것으로 생각된다.

• 대한화학회지
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• 제34권5호
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• pp.452-459
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• 1990

일련의 산소 및 황 가교결합의 이핵 몰리브덴(V) 착물, Mo$_2$O$_4$L$_2$, Mo$_2$O$_3$L$_4$, Mo$_2$O$_2$S$_2$L$_2$, 그리고 Mo$_2$OS$_3$L$_2$, L = bis(hydroxyethyl)dithiocarbamate을 합성하였다. 말단과 가교의 산소결합 착물은 수용액에서 (PyH)$_2$MoOCl$_5$ 혹은 MoCl$_5$와 리간드의 반응으로부터 합성되었고, Mo$_2$O$_4^{2+}$핵에서 산소가 황으로 치환된 착물, Mo$_2$O$_2$S$_2$L$_2$은 Mo$_2$OS$_3$L$_2$의 클로로포름 용액에 트리페닐포스핀을 가하므로 합성되었다. 한편, Mo$_2$OS$_3$L$_2$착물은 sodium dithionite 존재하에서 (NH$_4$)$_2$MoS$_4$와 리간드의 수용액으로부터 얻어졌다. 합성한 착물에 대한 원소분석과 ir, uv-vis, nmr, 그리고 mass 스펙트라에 의한 착물의 분광학적 성질을 조사하였다. 또한 디메틸술폭시드 용액에서 이들 착물의 전기화학적 성질을 순환전압-전류법으로 조사하였다.

• 한국분말재료학회지
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• 제23권4호
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• pp.303-306
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• 2016

An optimum route to synthesize Ti-Mo system powders is investigated by analyzing the effect of the heat treatment atmosphere on the formation of the reaction phase by dehydrogenation and hydrogen reduction of ball-milled $TiH_2-MoO_3$ powder mixtures. Homogeneous powder mixtures with refined particles are prepared by ball milling for 24 h. XRD analysis of the heat-treated powder in a hydrogen atmosphere shows $TiH_2$ and $MoO_3$ peaks in the initial powders as well as the peaks corresponding to the reaction phase species, such as $TiH_{0.7}$, TiO, $MoO_2$, Mo. In contrast, powder mixtures heated in an argon atmosphere are composed of Ti, TiO, Mo and $MoO_3$ phases. The formation of reaction phases dependent on the atmosphere is explained by the partial pressure of $H_2$ and the reaction temperature, based on thermodynamic considerations for the dehydrogenation reaction of $TiH_2$ and the reduction behavior of $MoO_3$.