Supported loaded semiconductors (MoO3,ZnO)-TiO2/SiO2 were pre pared by an isovolumetric impregnation method from TiO2/SiO2 pre pared by chemical modification reaction. The chemisorption property and photon a bsorpti...Supported loaded semiconductors (MoO3,ZnO)-TiO2/SiO2 were pre pared by an isovolumetric impregnation method from TiO2/SiO2 pre pared by chemical modification reaction. The chemisorption property and photon a bsorption ability of MoO3-TiO2/SiO2 and ZnO-TiO2/SiO 2 were investigated by BET, UV-Vis DRS, IR and TPD-MS techniques. The gas -phase photocatalytic reaction of CH4 with H2O was performed at 150 ℃ in a fixed-bed annular reactor. The results show that the conversion of met hane and the selectivity of methanol reach to 5.1% and 87.3% respectively over MoO3-TiO2/SiO2, and MoO3-TiO2/SiO2 ex hibits higher photocatalytic acivity than ZnO-TiO2/SiO2.展开更多
Er3+ doped potassium gadolinium molybdate (KGM) phosphor with sensitizer Yb3+ ion was synthesized by the Pechini method using citric acid and ethylene glycol. The crystallization processes of the phosphor precurso...Er3+ doped potassium gadolinium molybdate (KGM) phosphor with sensitizer Yb3+ ion was synthesized by the Pechini method using citric acid and ethylene glycol. The crystallization processes of the phosphor precursors were characterized by X-ray diffraction (XRD) and thermogravimetry-differential scanning calorimetry (TG-DSC), which indicated that ultrafine uniform crystallites of KGM:Er,Yb were obtained by sintering the precursors at above 650 ℃ for 5 h. Upconversion luminescence (UL) spectra of the samples were studied by a 976 nm semiconductor laser diode (LD) excitation. The UL spectra exhibited the green and red emission bands that were attributed to the 2H11/2, 4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3+, respectively. The possible UL mechanisms of Er3+ were explained by means of an energy level diagram. The maximum luminescent intensity was achieved when the concentration of Er3+, Yb3+ arrived at 1 mol.% and 20 mol.%, respectively.展开更多
A lithium ion conductive solid electrolyte, L20-AI203-TiO2-SiO2-P20s glass with NASICON- type structure have been synthesized and transformed into glass-ceramic through thermal-treatment at various temperatures from 7...A lithium ion conductive solid electrolyte, L20-AI203-TiO2-SiO2-P20s glass with NASICON- type structure have been synthesized and transformed into glass-ceramic through thermal-treatment at various temperatures from 700 to 1 000 ~C for 12 h. The differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and complex impedance techniques were employed to characterize the samples. The experimental results indicated that the capability of glass forming in this system is superior to that of L20-A1203-TiO2-PzO~. The glass has an amorphous structure and resultant glass-ceramic mainly consisting of LiTi2(PO4)3 phases. Impurity phases AIPO4, TiO2, TiP207 and unidentified phase were observed. With the enhanced heat-treatment temperature, grain grew gradually and lithium ion conductivity of glass-ceramics increased accordingly, the related impedance semicircles were depressed gradually and even disappeared, which could be analytically explained by the coordinate action of the 'Constant phase element' (CPE) model and the 'Concept of Mismatch and Relaxation' model (CMR). When the sample is devitrified at 1 000 ~C, the maximum room temperature lithium ion conductivity comes up to 4.1 x 10-4 S/cm, which is suitable for the application as an electrolyte of all-solid-state lithium batteries.展开更多
A new solid acid catalyst SO42-MoO3TiO2 was prepared.FT-IR data had indicted that the surface of the catalyst had strong acidic centers.FTIR spectra of pyridine absorbed on the surface showed that th...A new solid acid catalyst SO42-MoO3TiO2 was prepared.FT-IR data had indicted that the surface of the catalyst had strong acidic centers.FTIR spectra of pyridine absorbed on the surface showed that the catalyst had Bronsted acid site.The catalyst had high catalytic activity and excellent selectivity in esterification,acetalation and ketal formation as well as no corrosion to the facilities.The catalyst was an enviormentally friendly catalyst.展开更多
摘要Supported loaded semiconductors (MoO3,ZnO)-TiO2/SiO2 were pre pared by an isovolumetric impregnation method from TiO2/SiO2 pre pared by chemical modification reaction. The chemisorption property and photon a bsorption ability of MoO3-TiO2/SiO2 and ZnO-TiO2/SiO 2 were investigated by BET, UV-Vis DRS, IR and TPD-MS techniques. The gas -phase photocatalytic reaction of CH4 with H2O was performed at 150 ℃ in a fixed-bed annular reactor. The results show that the conversion of met hane and the selectivity of methanol reach to 5.1% and 87.3% respectively over MoO3-TiO2/SiO2, and MoO3-TiO2/SiO2 ex hibits higher photocatalytic acivity than ZnO-TiO2/SiO2.
基金Project supported by Shandong Province Natural Science Foundation (Y2008F10)the Award Fund for Prominent Youth Scientists of Shandong Province (2008BS09006)Shandong Province Higher Educational Science and Technology Program (J10LD1810-13)
摘要Er3+ doped potassium gadolinium molybdate (KGM) phosphor with sensitizer Yb3+ ion was synthesized by the Pechini method using citric acid and ethylene glycol. The crystallization processes of the phosphor precursors were characterized by X-ray diffraction (XRD) and thermogravimetry-differential scanning calorimetry (TG-DSC), which indicated that ultrafine uniform crystallites of KGM:Er,Yb were obtained by sintering the precursors at above 650 ℃ for 5 h. Upconversion luminescence (UL) spectra of the samples were studied by a 976 nm semiconductor laser diode (LD) excitation. The UL spectra exhibited the green and red emission bands that were attributed to the 2H11/2, 4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3+, respectively. The possible UL mechanisms of Er3+ were explained by means of an energy level diagram. The maximum luminescent intensity was achieved when the concentration of Er3+, Yb3+ arrived at 1 mol.% and 20 mol.%, respectively.
基金National Basic Research Program of China (No.2009CB939704)National Natural Science Foundation of China (Nos.51032005, 60808024)the Fundamental Research Funds for the Central Universities (Wuhan University of Technology)
摘要A lithium ion conductive solid electrolyte, L20-AI203-TiO2-SiO2-P20s glass with NASICON- type structure have been synthesized and transformed into glass-ceramic through thermal-treatment at various temperatures from 700 to 1 000 ~C for 12 h. The differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and complex impedance techniques were employed to characterize the samples. The experimental results indicated that the capability of glass forming in this system is superior to that of L20-A1203-TiO2-PzO~. The glass has an amorphous structure and resultant glass-ceramic mainly consisting of LiTi2(PO4)3 phases. Impurity phases AIPO4, TiO2, TiP207 and unidentified phase were observed. With the enhanced heat-treatment temperature, grain grew gradually and lithium ion conductivity of glass-ceramics increased accordingly, the related impedance semicircles were depressed gradually and even disappeared, which could be analytically explained by the coordinate action of the 'Constant phase element' (CPE) model and the 'Concept of Mismatch and Relaxation' model (CMR). When the sample is devitrified at 1 000 ~C, the maximum room temperature lithium ion conductivity comes up to 4.1 x 10-4 S/cm, which is suitable for the application as an electrolyte of all-solid-state lithium batteries.
摘要A new solid acid catalyst SO42-MoO3TiO2 was prepared.FT-IR data had indicted that the surface of the catalyst had strong acidic centers.FTIR spectra of pyridine absorbed on the surface showed that the catalyst had Bronsted acid site.The catalyst had high catalytic activity and excellent selectivity in esterification,acetalation and ketal formation as well as no corrosion to the facilities.The catalyst was an enviormentally friendly catalyst.