Molybdenum oxide films were fabricated successfully by spin coating from Li＋- doped peroxo- polymolybdate solution via sol- gel technique.Their electrochemical and electrochromic properties were investigated by cycli...Molybdenum oxide films were fabricated successfully by spin coating from Li＋- doped peroxo- polymolybdate solution via sol- gel technique.Their electrochemical and electrochromic properties were investigated by cyclic voltammetry and in- situ UV transmittance measurements.The results showed that the films possessed excellent electrochemical stability and reversibility.The electrochromic mechanism of the MoO3 was discussed by using results obtained from X- ray photoelectron spectroscopy (XPS).The results showed that the most part of the Mo6＋ in MoO3 film was reduced to Mo5＋ and Mo4＋ ions during the Li＋ intercalation process,Mo4＋ was oxidized to Mo5＋ and part of Mo5＋ was oxidized to Mo6＋ again during the Li＋ deintercalation process.So it was considered that Mo4＋ ions existed in the colored MoO3 films.展开更多
Plasmonic nonmetal semiconductors with localized surface plasmon resonance(LSPR)effects possess extended light-response ranges and can act as highly efficient H2 generation photocatalysts.Herein,an LSPR-enhanced 0D/2D...Plasmonic nonmetal semiconductors with localized surface plasmon resonance(LSPR)effects possess extended light-response ranges and can act as highly efficient H2 generation photocatalysts.Herein,an LSPR-enhanced 0D/2D CdS/MoO3‒x heterojunction has been synthesized by the growth of 0D CdS nanoparticles on 2D plasmonic MoO3‒x elliptical nanosheets via a simple coprecipitation method.Taking advantage of the LSPR effect of the MoO3‒x elliptical nanosheets,the light absorption of the CdS/MoO3‒x heterojunction was extended from 600 nm to the near-infrared region(1400 nm).Furthermore,the introduction of 2D plasmonic MoO3‒x elliptical nanosheets not only provided a platform for the growth of CdS nanoparticles,but also contributed to the construction of an LSPR-enhanced S-scheme structure due to the interface between the MoO3‒x and CdS,accelerating the separation of light-induced electrons and holes.Therefore,the CdS/MoO3‒x heterojunction exhibited higher photocatalytic H2 generation activity than pristine CdS under visible light irradiation,including under 420,450,550,and 650 nm monochromic light,as well as improved photo-corrosion performance.展开更多
Two-dimensional(2D)magnetic semiconductors are crucial in spin-based information-processing technologies due to the combination of the strong 2D quantum effects,surface effects and the control of spin states.However,m...Two-dimensional(2D)magnetic semiconductors are crucial in spin-based information-processing technologies due to the combination of the strong 2D quantum effects,surface effects and the control of spin states.However,most experimental approaches for tuning 2D magnets achieve pure ferromagnetism at low temperature.Herein,a defect engineering strategy using supercritical CO2 is introduced to achieve nanostructure with abundant defects for 2D MoO3−x,and room-temperature ferromagnetism can be obtained and tuned by introduction of the Mo5+ion depending on the change of supercritical pressure.In defective regions,the presence of the pentacoordinated[Mo5+O5]centers can achieve ferromagnetic ordering resulting in room-temperature ferromagnetism.With increasing supercritical pressure,it is easier for the supercritical CO2 to break the Mo–O bonds,achieving enhancement of the ferromagnetic performance with desired Curie temperature(>380 K).The magnetic responses in the MoO3−x system provide a step closer to the expansion of spin electronics.展开更多
Two series of molybdenum-containing MCM-41 catalysts were prepared for oxidative desulfurization ofdibenzothiophene （DBT） using t-butylhydroperoxide （TBHP） as the oxidant. The electronic properties, pore dimension...Two series of molybdenum-containing MCM-41 catalysts were prepared for oxidative desulfurization ofdibenzothiophene （DBT） using t-butylhydroperoxide （TBHP） as the oxidant. The electronic properties, pore dimension and hydrophilic properties of the catalysts were studied by XRD, BET, and 1R spectrometry. The Mo-Al2O3 catalyst and TiMCM-3% were also studied for comparison. The two series of MCM-41 zeolite with MoO3 in the framework or impregnated on the surface exhibited considerable activities at low MoO3 content and both were faxbetter than the Mo-Al2O3 catalyst, but had lower activities as compared to the TiMCM-3% catalyst. The catalysts with the highest activity were evaluated in a fixed-bed reactor. The concentration of DBT in model diesel upon oxidative desulfurization was successfully reduced from 5000 ppm to less than 150 ppm, but the catalysts were deactivated very fast. The probable reason was the high affinity of DBTO2 to the MCM-41 skeleton, especially to MoO3. The catalysts could restore most of its original activity by treating with alcohol.展开更多
文摘Molybdenum oxide films were fabricated successfully by spin coating from Li＋- doped peroxo- polymolybdate solution via sol- gel technique.Their electrochemical and electrochromic properties were investigated by cyclic voltammetry and in- situ UV transmittance measurements.The results showed that the films possessed excellent electrochemical stability and reversibility.The electrochromic mechanism of the MoO3 was discussed by using results obtained from X- ray photoelectron spectroscopy (XPS).The results showed that the most part of the Mo6＋ in MoO3 film was reduced to Mo5＋ and Mo4＋ ions during the Li＋ intercalation process,Mo4＋ was oxidized to Mo5＋ and part of Mo5＋ was oxidized to Mo6＋ again during the Li＋ deintercalation process.So it was considered that Mo4＋ ions existed in the colored MoO3 films.
文摘Plasmonic nonmetal semiconductors with localized surface plasmon resonance(LSPR)effects possess extended light-response ranges and can act as highly efficient H2 generation photocatalysts.Herein,an LSPR-enhanced 0D/2D CdS/MoO3‒x heterojunction has been synthesized by the growth of 0D CdS nanoparticles on 2D plasmonic MoO3‒x elliptical nanosheets via a simple coprecipitation method.Taking advantage of the LSPR effect of the MoO3‒x elliptical nanosheets,the light absorption of the CdS/MoO3‒x heterojunction was extended from 600 nm to the near-infrared region(1400 nm).Furthermore,the introduction of 2D plasmonic MoO3‒x elliptical nanosheets not only provided a platform for the growth of CdS nanoparticles,but also contributed to the construction of an LSPR-enhanced S-scheme structure due to the interface between the MoO3‒x and CdS,accelerating the separation of light-induced electrons and holes.Therefore,the CdS/MoO3‒x heterojunction exhibited higher photocatalytic H2 generation activity than pristine CdS under visible light irradiation,including under 420,450,550,and 650 nm monochromic light,as well as improved photo-corrosion performance.
基金the National Natural Science Foundation of China(No.21773216,51173170)the Henan-Provincial and the China-National Natural Science United Foundation(Project No.U2004208).
文摘Two-dimensional(2D)magnetic semiconductors are crucial in spin-based information-processing technologies due to the combination of the strong 2D quantum effects,surface effects and the control of spin states.However,most experimental approaches for tuning 2D magnets achieve pure ferromagnetism at low temperature.Herein,a defect engineering strategy using supercritical CO2 is introduced to achieve nanostructure with abundant defects for 2D MoO3−x,and room-temperature ferromagnetism can be obtained and tuned by introduction of the Mo5+ion depending on the change of supercritical pressure.In defective regions,the presence of the pentacoordinated[Mo5+O5]centers can achieve ferromagnetic ordering resulting in room-temperature ferromagnetism.With increasing supercritical pressure,it is easier for the supercritical CO2 to break the Mo–O bonds,achieving enhancement of the ferromagnetic performance with desired Curie temperature(>380 K).The magnetic responses in the MoO3−x system provide a step closer to the expansion of spin electronics.
文摘Two series of molybdenum-containing MCM-41 catalysts were prepared for oxidative desulfurization ofdibenzothiophene （DBT） using t-butylhydroperoxide （TBHP） as the oxidant. The electronic properties, pore dimension and hydrophilic properties of the catalysts were studied by XRD, BET, and 1R spectrometry. The Mo-Al2O3 catalyst and TiMCM-3% were also studied for comparison. The two series of MCM-41 zeolite with MoO3 in the framework or impregnated on the surface exhibited considerable activities at low MoO3 content and both were faxbetter than the Mo-Al2O3 catalyst, but had lower activities as compared to the TiMCM-3% catalyst. The catalysts with the highest activity were evaluated in a fixed-bed reactor. The concentration of DBT in model diesel upon oxidative desulfurization was successfully reduced from 5000 ppm to less than 150 ppm, but the catalysts were deactivated very fast. The probable reason was the high affinity of DBTO2 to the MCM-41 skeleton, especially to MoO3. The catalysts could restore most of its original activity by treating with alcohol.
