A series of NiO/SiO2 aerogel catalysts were prepared by sol gel method. The effects of the nickel content on the structure and existing forms of NiO/SiO2 aerogel catalysts were investigated by using XRD, TPR and FT IR...A series of NiO/SiO2 aerogel catalysts were prepared by sol gel method. The effects of the nickel content on the structure and existing forms of NiO/SiO2 aerogel catalysts were investigated by using XRD, TPR and FT IR. The results showed that there were interactions between NiO and SiO2. But as nickel content increased, the interaction decreased. The nickel oxide in the catalysts appeared in different forms as nickel content was changed. When the content was less than 13%, Ni? entered into the SiO2 structure completely and it became clusters after calcining. If the content altered from 20% to 50%, NiO existed as both microcrystal and clusters, the later spices was dominating. However, when the content increased to 70%, microcrystal became the primary components.展开更多
A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The struct...A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The structural features of the TiO2/SiO2-Al2O3 aerogel composite were investigated by X-ray powder diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,gas adsorption measurements and diffuse reflectance UV-visible spectroscopy.The optimal conditions for photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol（DNBP],included an initial DNBP concentration of 0.167 mmol/L at pH = 4.86 with a catalyst concentration of 6 g/L,under visible light irradiation for 5 h.A plausible mechanism is proposed for the photocatalytic degradation of DNBP.Our composite showed higher photocatalytic activity for DNBP degradation than that of pure TiO2.This indicates that this material can serve as an efficient photocatalyst for degradation of hazardous organic pollutants in wastewater.展开更多
TiO2/SiO2 aerogels with different molar ratio of SiO2/TiO2 were prepared via non-supercritical method using tetrabutyl titanate and silica sols as raw materials. The samples were characterized by TEM, SEM, BET, IR, XR...TiO2/SiO2 aerogels with different molar ratio of SiO2/TiO2 were prepared via non-supercritical method using tetrabutyl titanate and silica sols as raw materials. The samples were characterized by TEM, SEM, BET, IR, XRD and so on. The results indicate that the BET surface area of TiO2/SiO2 aerogels calcined at 550℃ which consisted of anatase structure of TiO2 with narrow distribution pores of 5-25 nm is as high as 357.89 m2·g-1. For the photocatalytic degradation of pyridine, the catalytic activities of TiO2/SiO2 aerogels are much higher than that of TiO2 powder. The photocatalytic activity of TiO2/SiO2 aerogels calcined at 800℃ is the optimum. The higher the content of SiO2, the higher the photocatalytic activity of TiO2/SiO2 aerogels. The cost for preparation of the aerogels is greatly reduced by using non-supercritical drying method, and the aerogels are hopefully applied in the treatment of industrial waste water such as coking effluent treatment.展开更多
The hydrophobic SiO2 aerogels were prepared by in-situ polymerization sol-gel method and supercritical drying of ethanol method with tetraethylorthosilicate（TEOS） as silica source, methyl triethoxysilane （MTMS） as...The hydrophobic SiO2 aerogels were prepared by in-situ polymerization sol-gel method and supercritical drying of ethanol method with tetraethylorthosilicate（TEOS） as silica source, methyl triethoxysilane （MTMS） as modifier, ethanol as solvent. Moreover, the structure and adsorption property of SiO2 aerogels were also studied. As results, the surface area of SiO2 aerogels was 863.59 m2/g, the pore volume was 3.57 cm3/g, and the contact angle was 150 °. Adsorption intensity of silica aerogels for organic liquid （alkanes, benzene compounds, and nitro-compounds） is bigger than that of activated carbon. The mass of the liquid absorbed increased linearly with the surface tension of the liquid. The lower surface tension and boiling point are, the shorter desorption time is. After regenerating 10 times, nitromethane regeneration rate remain the same, and almost more than 94%. So SiO2 aerogels have good absorption and regeneration property.展开更多
An ambient pressure synthesis of SiO2/TiO2 binary aerogel was prepared through the low-cost precursors of titanium tetrachloride（TiCl4） and sodium silicate（Na2O·nSiO2）.After gelation,solvent exchange and surf...An ambient pressure synthesis of SiO2/TiO2 binary aerogel was prepared through the low-cost precursors of titanium tetrachloride（TiCl4） and sodium silicate（Na2O·nSiO2）.After gelation,solvent exchange and surface modification were performed simultaneously and the modified gel was finally dried under ambient pressure.Microstructural analyses by transmission electron microscope（TEM） indicate that fabricated SiO2/TiO2 aerogel composite shows similar sponge-like nanostructure as silica aerogel,and the Brunauer-EmmettTeller（BET） analysis shows that the specific surface area of the composite reaches 605 m^2/g,and the average pore size is 9.7 nm.Such binary aerogel exhibits significant photocatalytic performance in this paper for treating model pollutant of methyl orange（MO）,and the decolorizing efficiency of MO is detected as 84.9%after 210 mins exposure to UV light irradiation.Degraded gel suspends in the water so as to separate from solution for reuse,and after 4 times recycling,70%degradation efficiency can be easily reached when composite catalyzed system is exposed for 210 mins under UV irradiation.展开更多
文摘A series of NiO/SiO2 aerogel catalysts were prepared by sol gel method. The effects of the nickel content on the structure and existing forms of NiO/SiO2 aerogel catalysts were investigated by using XRD, TPR and FT IR. The results showed that there were interactions between NiO and SiO2. But as nickel content increased, the interaction decreased. The nickel oxide in the catalysts appeared in different forms as nickel content was changed. When the content was less than 13%, Ni? entered into the SiO2 structure completely and it became clusters after calcining. If the content altered from 20% to 50%, NiO existed as both microcrystal and clusters, the later spices was dominating. However, when the content increased to 70%, microcrystal became the primary components.
基金supported by the National Natural Science Foundation of China(21377018)the Natural Science Foundation of Liaoning Province of China(2013020116)the Fundamental Research Funds for the Central Universities(DUT15ZD240)~~
文摘A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The structural features of the TiO2/SiO2-Al2O3 aerogel composite were investigated by X-ray powder diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,gas adsorption measurements and diffuse reflectance UV-visible spectroscopy.The optimal conditions for photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol（DNBP],included an initial DNBP concentration of 0.167 mmol/L at pH = 4.86 with a catalyst concentration of 6 g/L,under visible light irradiation for 5 h.A plausible mechanism is proposed for the photocatalytic degradation of DNBP.Our composite showed higher photocatalytic activity for DNBP degradation than that of pure TiO2.This indicates that this material can serve as an efficient photocatalyst for degradation of hazardous organic pollutants in wastewater.
基金Supported by the National Natural Science Foundation of China (No. 20473057)Development Foundation of Science and Technology of Shanghai (No. 0352nm094).
文摘TiO2/SiO2 aerogels with different molar ratio of SiO2/TiO2 were prepared via non-supercritical method using tetrabutyl titanate and silica sols as raw materials. The samples were characterized by TEM, SEM, BET, IR, XRD and so on. The results indicate that the BET surface area of TiO2/SiO2 aerogels calcined at 550℃ which consisted of anatase structure of TiO2 with narrow distribution pores of 5-25 nm is as high as 357.89 m2·g-1. For the photocatalytic degradation of pyridine, the catalytic activities of TiO2/SiO2 aerogels are much higher than that of TiO2 powder. The photocatalytic activity of TiO2/SiO2 aerogels calcined at 800℃ is the optimum. The higher the content of SiO2, the higher the photocatalytic activity of TiO2/SiO2 aerogels. The cost for preparation of the aerogels is greatly reduced by using non-supercritical drying method, and the aerogels are hopefully applied in the treatment of industrial waste water such as coking effluent treatment.
基金Funded by the National Natural Science Foundation of China (No. 10976013)the Science Project of Ministry of Housing and Urban-Rural Development(No. 2011-K7-16)+1 种基金the State Key Laboratory of Materials-Oriented Chemical Engineeringthe Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The hydrophobic SiO2 aerogels were prepared by in-situ polymerization sol-gel method and supercritical drying of ethanol method with tetraethylorthosilicate（TEOS） as silica source, methyl triethoxysilane （MTMS） as modifier, ethanol as solvent. Moreover, the structure and adsorption property of SiO2 aerogels were also studied. As results, the surface area of SiO2 aerogels was 863.59 m2/g, the pore volume was 3.57 cm3/g, and the contact angle was 150 °. Adsorption intensity of silica aerogels for organic liquid （alkanes, benzene compounds, and nitro-compounds） is bigger than that of activated carbon. The mass of the liquid absorbed increased linearly with the surface tension of the liquid. The lower surface tension and boiling point are, the shorter desorption time is. After regenerating 10 times, nitromethane regeneration rate remain the same, and almost more than 94%. So SiO2 aerogels have good absorption and regeneration property.
基金Funded by the National Natural Science Foundation of China(NSFC)(Nos.51278073,51308079 and 51408073)
文摘An ambient pressure synthesis of SiO2/TiO2 binary aerogel was prepared through the low-cost precursors of titanium tetrachloride（TiCl4） and sodium silicate（Na2O·nSiO2）.After gelation,solvent exchange and surface modification were performed simultaneously and the modified gel was finally dried under ambient pressure.Microstructural analyses by transmission electron microscope（TEM） indicate that fabricated SiO2/TiO2 aerogel composite shows similar sponge-like nanostructure as silica aerogel,and the Brunauer-EmmettTeller（BET） analysis shows that the specific surface area of the composite reaches 605 m^2/g,and the average pore size is 9.7 nm.Such binary aerogel exhibits significant photocatalytic performance in this paper for treating model pollutant of methyl orange（MO）,and the decolorizing efficiency of MO is detected as 84.9%after 210 mins exposure to UV light irradiation.Degraded gel suspends in the water so as to separate from solution for reuse,and after 4 times recycling,70%degradation efficiency can be easily reached when composite catalyzed system is exposed for 210 mins under UV irradiation.
