• Title/Summary/Keyword: $MoO_x$

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Synthesis and Characterization of Substituted Pyridine Complexes of Molybdenum(Ⅴ). Di-${\mu}$-oxo-dioxodichlorobis(substituted pyridines) dimolybdenum(Ⅴ) and Substituted Pyridinium Di-${\mu}$-oxo-dioxohexaisothiocyanatodimolybdates(Ⅴ) (몰리브덴의 피리딘계 착물합성과 그 성질 (제5보). 이-${\mu}$ -옥소-이옥소이클로로비스(치환피리딘) 이 몰리브덴 (Ⅴ) 와 이-${\mu}$- 옥소-이옥소육이소티오시아나토 이 몰리브덴 (Ⅴ) 산 치환피리딘늄)

  • Kim, Chang-Su;Sang Oh Oh
    • Journal of the Korean Chemical Society
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    • v.26 no.6
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    • pp.383-388
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    • 1982
  • $Mo_2O_4Cl_2$$(X-py)_4{\cdot}2H_2$O and $(X-pyH)_4$[$Mo_2O_4(NCS)_6)$]${\cdot}H_2$O have been prepared. The infrared, electronic and reflectance spectra, molar conductances and magnetic susceptibility data of complexes are reported. $Mo_2O_4Cl_2$$(X-py)_4{\cdot}2H_2$O (X-py were 3-and 4-cyanopyridine, nicotinamide, 3,5-lutidine and 2-amino-4-picoline) were obtained by hydrolysis of the corresponding substituted pyridinium oxopentachloromolybdates(Ⅴ). Addition of water and substituted pyridines to molybdenum(Ⅴ)-thiocyanate ethylacetate extract yielded brown compounds, $(X-pyH)_4$[$Mo_2O_4(NCS)_6)$]${\cdot}H_2$O where X-py were pyridine, ${\alpha}$, 3-bromopyridine 3,5-lutidine, 3-benzoylpyridine and 4-acetylpyridine. Binuclear, $Mo_2O_4Cl_2(X-py)_4{\cdot}2H_2$ prepared from hydrolysis of $(X-pyH)_2[MoOCl_5]{\cdot}H_2O$ were diamagnetic and nonelectrolytes. The anion of $(X-pyH)_4$[$Mo_2O_4(NCS)_6)$]${\cdot}H_2$O was formulated as dimer and electrolyte.

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Effect of MoOx Overlayer on Hydrogen Spillover Kinetics over Pt/MoO3 (Pt/MoO3 촉매에 형성된 MoOx 박막이 수소 전이 속도론에 미치는 효과)

  • Kim, Jin-Gul;Kim, Seong-Soo;Yoo, Seung-Joon
    • Transactions of the Korean hydrogen and new energy society
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    • v.20 no.1
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    • pp.73-78
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    • 2009
  • 투과 전자 현미경(TEM)을 사용하여 소성 후 Pt와 $MoO_3$ 표면 위에 $MoO_x$ 박막층이 형성되는 것을 조사하였다. 연속된 CO 화학 흡착법에 의하여 표면된 노출된 Pt 표면적의 변화를 관찰하였으며, XPS 분석으로 부터 Pt 표면에 형성된 $MoO_x$ 박막층 두께는 소성 온도 증가에 따라 증가하는 것으로 측정되었다. 소성 과정은 Pt와 $MoO_3$ 간에 개선된 접촉을 유도하였으며, Pt/$MoO_3$ 촉매에서 수소전이현상을 조절하는 것으로 나타난다.

MoOx-Windowed High-Performing Transparent Photodetector (MoOx 기반의 고성능 투명 광검출기)

  • Park, Wang-Hee;Lee, Gyeongnam;Kim, Joondong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.30 no.6
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    • pp.387-392
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    • 2017
  • A high-performing all-transparent photodetector was created by configuring a $MoO_x$/NiO/ZnO/ITO structure on a glass substrate. The ITO bottom layer was applied as a back contact. To achieve the transparent p/n junction, p-type NiO was coated on the n-type ZnO layer. Reactive sputtering was used to spontaneously form the ZnO or NiO layer. In order to improve the transparent photodetector performance, the functional $MoO_x$ window layer was used. Optically, the $MoO_x$ window provided a refractive index layer (n=1.39) lower than that of NiO (n=2), increasing the absorption of the incident light wavelengths (${\lambda}s$). Moreover, the $MoO_x$ window can provide a lower sheet resistance to improve the carrier collection for the photoresponses. The $MoO_x$/NiO/ZnO/ITO device showed significantly better photoresponses of 877.05 (at ${\lambda}$=460nm), 87.30 (${\lambda}$=520 nm), and 30.38 (${\lambda}$=620 nm), compared to 197.28 (${\lambda}$=460 nm), 51.74 (${\lambda}$=520 nm) and 25.30 (${\lambda}$=620 nm) of the NiO/ZnO/ITO device. We demonstrated the high-performing transparent photodetector by using the multifunctional $MoO_x$ window layer.

Emission Characteristics of Blue Fluorescence Tandem OLED Using MoOx (MoOx를 사용한 청색 형광 Tandem OLED의 발광 특성)

  • Kwak, Tea-Ho;Ju, Sung-Hoo
    • Journal of the Korean institute of surface engineering
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    • v.47 no.3
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    • pp.104-108
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    • 2014
  • To improve emission efficiency of organic light emitting devices (OLEDs), we fabricated the tandem OLED of ITO / 2-TNATA / NPB / SH-1: 3 vol.% BD-2 / Bphen / Liq / Al / $MoO_x$ (X nm) / 2-TNATA / NPB / SH-1: 3 vol.% BD-2 / Bphen / Liq / Al structure. And emission properties of single OLED and tandem OLED with $MoO_x$ thickness as charge generation layer (CGL) were measured. The current emission efficiency and quantum efficiency of tandem OLED with $MoO_x$ of 3 nm thickness were improved compare with single OLED from 7.46 cd/A and 5.39% to 22.57 cd/A and 11.76%, respectively. In case of thicker or thinner than $MoO_x$ of 3~5 nm, the current emission efficiency and quantum efficiency were decreased, because balance of electron and hole in emission layer was not matching. The driving voltage was increased from 8 V of single OLED to 15 V of tandem OLED by thickness increase of OLED. As a result, it was possible to improve the emission efficiency of OLEDs by optimized $MoO_x$ thickness.

Synthesis of PbMo1-xCrxO4 Oxides Prepared Using Hydrothermal Process and their Photocatalytic Activity (수열합성법에 의한 PbMo1-xCrxO4 산화물의 합성 및 광촉매 활성)

  • Song, Young In;Hong, Seong-Soo
    • Applied Chemistry for Engineering
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    • v.26 no.6
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    • pp.714-718
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    • 2015
  • Both lead molybdate ($PbMoO_4$) and chromium substituted lead molybdate ($PbMo_{1-x}Cr_xO_4$) were successfully synthesized using a conventional hydrothermal method and characterized by XRD, DRS, Raman, SEM and PL. We also investigated the photocatalytic activity of these materials for the decomposition of rhodamine B under UV-visible irradiation. The XRD and Raman results revealed the successful synthesis of well-crystallized $PbMoO_4$ crystals with the diameter of 51-59 nm, regardless of the addition of chromium ion. The DRS spectra of $PbMo_{1-x}Cr_xO_4$ catalysts showed new intensive absorption bands in the visible region. The $PbMoO_4$ catalysts showed the lowest photocatalytic activity and the activity increased with an increase of chromium substitution amounts under visible irradiation. PL peaks appeared at about 540-580 nm for all catalysts and excitonic PL signals were proportional to the photocatalytic activity for the decomposition of rhodamine B.

Electronic Structure of Iron and Molybdenum in $Li_2FeMoO_4Cl$ and Its Crystal Symmetry ($Li_2FeMoO_4Cl$의 결정구조와 Fe 및 Mo의 전자구조 연구)

  • Choy, Jin-Ho;Park, Nam-Gyu;Chang, Soon-Ho;Park, Hyung-Ho
    • Journal of the Korean Chemical Society
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    • v.39 no.6
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    • pp.446-452
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    • 1995
  • Lithium intercalates, $Li_xFeMoO_4Cl$ ($1{\leq}X{\leq}2$) prepared by electrochemical lithiation of $FeMoO_4Cl$ crystallizes in monoclinic structure for all x values as revealed by x-ray diffraction and galvanostatic discharge experiments. According to the x-ray photoelectron spectroscopic study, Fe(III) is at first reduced to Fe(II) upon lithium intercalation with the x domain of $0{\leq}X{\leq}1$, where the crystal symmetry is changed from tetragonal to monoclinic. On the other hand, Mo(VI) is reduced to lower valent state upon further lithium intercalation ($1{\leq}X{\leq}2$), where no crystal symmetry transformation and reduction of Fe(II) to lower valent state are observed. The Mo 3d spectrum for $Li_2FeMoO_4Cl$ appears as a complex shape, but can be deconvoluted into the three sets of the doublet on the basis of Gaussian function, those which correspond to Mo(VI), Mo(V) and Mo(IV) states, respectively. The mixed valent states of molybdenum after further lithiation may be due to a competitive reaction between the formation of Mo(V) and its disproportionation to Mo(IV) and Mo(VI).

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Effect of Temperature on $H_2$ Spillover over $Pt/H_xMoO_3$ (Pt를 담지한 $H_xMoO_3$촉매의 수소 이동 속도에 미치는 온도의 영향)

  • 김진걸
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.5 no.2
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    • pp.114-117
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    • 2004
  • Rates of $H_2$ uptake into $Pt/MoO_3$ were measured for the noncalcined and $200^{\circ}C$ calcined $Pt/MoO_3$. Amount of $H_2$ uptake for $200^\circ{C}$calcined $Pt/MoO_3$ was greater than the amount of noncalcined $Pt/MoO_3$. From these two experiments, it was found that the rates of $H_2$ desorption were proportional to the increase of desorption temperature. XPS demonstrated that Cl reduced more faster in ITR after calcination at $200^{\circ}C$. This inducd smaller amount of residual chlorine at adlineation sites between Pt and $MoO_3$ substrates. This resulted in opening the more channel of hydrogen pathway into more $MoO_3$particles and controled the kinetics of hydrogen uptake.

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Synthesis and Characterization of Substituted Pyridine Complexes of Molybdenum (Ⅳ). Oxotrichlorobis(substituted pyridine) molybdenum (Ⅴ) (몰리브덴의 피리딘계 착물합성과 그 성질 (제4보) 옥소삼클로로비스(치환피리딘)몰리브덴 (V))

  • Chang Su Kim;Sang Oh Oh
    • Journal of the Korean Chemical Society
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    • v.26 no.6
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    • pp.378-382
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    • 1982
  • Green crystalline salts of substituted pyridinium oxopentachloromolybdates(V) were obtained from concentrated hydrochloric acid solution of molybdenum(V)-thiocyanate extract. $MoOCl_3(X-py)_2$ (X-py were 4-and 3-cyanopyridine, 2-amino-4-picoline and 4-acetylpyridine) were obtained by reflux of the corresponding substituted pyridinium salts of oxopentachloromolybdates(Ⅴ) in absolute ethanol. ($X-pyH_2$)[$MoOCl_5$]$H_2$O containing the $MoO^{3+}$ group are dissolved and hydrolysed in water but $MoOCl_3(X-py)_2$ are insoluble in water, alcohol and acetone. The complexes are paramagnetic compounds.

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Studies on the Preparation for the Simultaneous Removal of NO and $SO_2$ from Stationary Sources I.Surface properties and reactivity of $V_2O_5-MoO_3/TiO_2$ catalysts (고정원에서 배출되는 $NO_x/SO_x$의 동시제거를 위한 SCR 촉매의 제조법에 관한 연구: I. $V_2O_5-MoO_3/TiO_2$ 촉매들의 표면특성과 반응성)

  • 구미화;정석진
    • Journal of Korean Society for Atmospheric Environment
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    • v.8 no.1
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    • pp.58-67
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    • 1992
  • For removing $NO_x$ and $SO_x$ from the flue gases emitted from stationary sources, $V_2O_5-MoO_3/TiO_2$ catalysts were prepared by the conventional impregnation method (aqueous solution) and a sort of surface fixation method(nonaqueous solution) as reported excellent reproducibility catalysts. And these catalysts observed their catalytic activities as well as their surface properties. V-Mo-O oxide, prepared from nonaqueous solution of $VOCl_3$ and $Mo(CO)_6$ and aqeous solution method, was supported as amorphous state by XRD and SEM measurements. The infrared spectra of fresh and used catalysts showed that in used catalysts, V=O bands decreased and new bands of vanadium oxysulfate bands were very sensitive. So the catalysts prepared from nonaqueous solution may bring about the high activity. Results from catalytic activity measurements at 350$^\circ$C, in the presence of $SO_2, NO$ conversion was more increased than in absence of $SO_2$. As the $MoO_3$ was added to $V_2O_5/TiO_2 system, SO_2$ conversion increased. It found that from the results, $V_2O-5-MoO_3/TiO_2$ catalysts prepared from an nonaqueous solution may bring about the high activity for both the reaction of NO and $SO_2$ removal.

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Study on Formation and Properties of Dioxomolybdenum Complexes (디옥소몰리브덴 착물의 합성과 그 성질에 대한 연구)

  • Sang-Oh Oh;Bon-Kweon Koo
    • Journal of the Korean Chemical Society
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    • v.30 no.5
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    • pp.441-448
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    • 1986
  • Dioxobis(sub.-salicylaldiminato) molybdenum (VI) complexes, $MoO_2\;(X-sal-N-R)_2,\;(X=H,\;5-CH_3,\;R=C_6H_5,\;p-F-C_6H_4,\;m-Cl-C_6H_4,p-I-C_6H_4\;and\;p-C_2H_5-C_6H_4)$, have been prepared by reactions of dioxobis(sub.-salicylaldehydato) molybdenum (VI), $MoO_2(X-sal)_2$ with primary amines, in which $MoO_2(X-sal)_2$ complexes were obtained by acidification of a mixture solution of ammonium paramolybdate in water and appropriate salicylaldehyde in methanol. All these complexes show two strong Mo=O stretching imodes in the 900-940$cm^{-1}$ and p.m.r. spectra exhibited only one signal for the azomethine group. These results confirmed that the complexes are six-coordinated octahedron with a $cis-MoO_2$ group and the geometrical configurations of the complexes possess a C2 axis of symmetry. From the mass analyses of the complexes, it found that the composition ratios of $MoO_2$ : ligand are 1 : 2. The charge transfer transition corresponding to N-Mo, and O-Mo occured at 29,000$cm^{-1}$ and 32,000$cm^{-1}$ respectively. Where, the complexes were found to be non-ionic materials by conductivity measurements in dimethylformamide.

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