CuO-CoO-MnO/SiO2 nanocomposite aerogels were prepared by using tetraethyl orthosilicate （TEOS） as Si source, and aqueous solution of Cu, Co and Mn acetates as transition metal sources via sol-gel process and supercr...CuO-CoO-MnO/SiO2 nanocomposite aerogels were prepared by using tetraethyl orthosilicate （TEOS） as Si source, and aqueous solution of Cu, Co and Mn acetates as transition metal sources via sol-gel process and supercritical drying （SCD） technique. The effect of synthesis conditions on gelation was investigated. Moreover, the composition of the CuO-CoO-MnO/SiO2 nanocomposite aerogels was characterized by electron dispersive spectroscopy （EDS） and X-ray photoelectron spectroscopy （XPS）, and the specific surface area of the nanocomposite aerogels was determined by the Brunauer-Emmett-Teller （BET） method. Diphenyl carbonate （DPC） as the product was analyzed by gas chromatography （GC）. The experimental results show that the range of optimal temperature for gelation is 30-45 ℃, and the pH is 3.0-4.5. CuO-CoO-MnO/SiO2 nanocomposite aerogels are porous with a specific surface area of 384.9-700.6 m2/g. Compared to CO2 SCD, ethanol SCD is even favorable to the formation of aerogel with high specific surface area. The transition metals content in the nanocomposite aerogels can be controlled to be 0.71at%-13.77at%. With CuO-CoO-MnO/SiO2 nanocomposite aerogels as catalyst carrier, the yield of DPC is in direct proportion to the atomic fraction of transition metals in the nanocomposite aerogels, and it is up to 26.31 mass%, which is much higher than that via other porous carriers.展开更多
Recently,methane of possible abiogenic origin has been reported from many localities within the Earth’s crust.However,little is known about the mechanisms of abiogenic methane formation during such processes.The Fisc...Recently,methane of possible abiogenic origin has been reported from many localities within the Earth’s crust.However,little is known about the mechanisms of abiogenic methane formation during such processes.The Fischer-Tropsch reaction as a well known process for converting CO<sub>2</sub> to hydrocarbon gas by reaction with H<sub>2</sub> may take place on a metallic iron or iron oxide catalyst and also may take place on展开更多
The effects of CeO2 contents and silica carrier porosity with their pore diameters ranging from 5.2 nm to 12.5 nm of CuO-CeO2/SiO2 cata-lysts in CO oxidation were investigated.The catalysts were characterized by N2 ad...The effects of CeO2 contents and silica carrier porosity with their pore diameters ranging from 5.2 nm to 12.5 nm of CuO-CeO2/SiO2 cata-lysts in CO oxidation were investigated.The catalysts were characterized by N2 adsorption/desorption at low temperature,X-ray diffraction （XRD）,temperature-programmed reduction by H2 （H2-TPR）,oxygen temperature programmed desorption （O2-TPD） and X-ray photoelectron spectroscopy （XPS）.The results suggested that,the ceria content and the porosity of SiO2 carrier possessed great impacts on the structures and catalytic performances of CuO-CeO2/SiO2 catalysts.When appropriate content of CeO2 （Ce content 8 wt%） was added,the catalytic activity was greatly enhanced.In the catalyst supported on silica carrier with larger pore diameter,higher dispersion of CuO was observed,better agglomeration-resistant capacity was displayed and more lattice oxygen could be found,thus the CuO-CeO2 supported on Si-1 showed higher catalytic activity for low-temperature CO oxidation.展开更多
The K2Ti4O9 whiskers were chosen for the catalyst carrier, TiO2/potassium titanate photocatalyst was prepared by Sol-gel method. The product was characterated by X-ray diffraction and SEM. EDS shows that, the main pec...The K2Ti4O9 whiskers were chosen for the catalyst carrier, TiO2/potassium titanate photocatalyst was prepared by Sol-gel method. The product was characterated by X-ray diffraction and SEM. EDS shows that, the main peck included Ti, O, and K in potassium titanate whisker. The main peak of K disappeared and the peaks of Ti, O stayed after whisker was covered. It directed that the surface of sample was covered by TiO2. XRD shows that diffraction peak appeared, which was corresponded to the peak of anatase TiO2. In the reaction device of photochemistry, using middle-pressure mercury lamp as illumination, rhodamine B as simulant pollutant, the photocatalytic performance of TiO2/potassium titanate was studied. Under the same conditions, the lower pH, the larger illuminance, the higher temperature, the greater aeration quantum and the lower initial concentration of rhodamine B, the higher decoloration rate was got. Under our experiment conditions: pH 6, the illuminance of 250W, the temperature of 313K, and the aeration quantum of 2.0L/min. When the concentration of rhodamine B was 8mg/L The photocatalyst of TiO2/potassium titanate was 0.01g/L. The decoloration rate of TiO2/potassium titanate dealt with the rhodamine B reach over 95% in 160min, and compare with TiO2, the decoloration rate of rhodamine B was improved 0.50~1.91 multiple. TiO2/potassium titanate can be used to treatment of dye wastewater.展开更多
The catalytic performances of Co3O4/SiO2 catalysts prepared by incipient wetness impregnation for CO oxidation were investigated using three kinds of silica as carriers with different pore sizes of 7.7,14.0 and 27.0 n...The catalytic performances of Co3O4/SiO2 catalysts prepared by incipient wetness impregnation for CO oxidation were investigated using three kinds of silica as carriers with different pore sizes of 7.7,14.0 and 27.0 nm.The effects of calcination temperature on the catalyst surface and micro structure properties as well as catalytic performance for the oxidation of carbon monoxide were also studied.All catalysts were characterized by N2 adsorption-desorption,XRD,XPS,FTIR,H2-TPR and O2-TPD.It was found that the properties and crystal size of cobalt-containing species strongly depended on the pore size of silica carrier.While the silica pore size increased from 7.7 to 27.0 nm,the Co3O4 crystal size increased from 8.5 to 13.5 nm.Moreover,it was demonstrated that if the spinel crystal structure of Co3O4 was obtained at a calcination temperature as low as 150℃,the catalyst sample would have a high Co3O4 surface dispersion and an increase of surface active species,and thus exhibit a high activity for the oxidation of carbon monoxide.展开更多
This paper describes the influences of active metal, promoter and chelating agent on the properties of hydro-desulfuri-zationcatalyst. The use of chelating agent, especially its combination with common promoters e.g.,...This paper describes the influences of active metal, promoter and chelating agent on the properties of hydro-desulfuri-zationcatalyst. The use of chelating agent, especially its combination with common promoters e.g., EDTA-P, has an important meaning to develop highly active catalyst, specifically to unify the active metal dispersion degree and sulfurization degree in some extent, however, they are contradictory in conventional cognition. In the aspect of carriers, composition and nanometer carriers have more excellent performances in acidity, pores structureand metal-carrier interaction than common carriers, and are the developing trend in the future and should be a breakthrough mainly in preparation methods. We also pointed out the decisive factors to improve the activity of the catalyst: higher sulfurization degree of active metal oxide and higher aspect ratios of active phase crystal morphology, and the proper acidity and pores structure can be considered the key factors for deep desulfurization whose mainly obstacle is the desulfurization of large rigid molecules, e.g., dibenzothiophene and 4, 6-dimethyl substituted dibenzothiophene. Based on above that, We discussed the suitable hydrodesulfurization (HDS) catalyst for coal tar, aiming at providing some theoretical guidance for the “design” of coal tar HDS catalyst.展开更多
基金Funded by the Hebei Natural Science Foundation(No.E2011209003)the Science and Technology Development Foundation of Hebei (No. 10215606D)the Ph D Programs Foundation of Hebei United University
文摘CuO-CoO-MnO/SiO2 nanocomposite aerogels were prepared by using tetraethyl orthosilicate （TEOS） as Si source, and aqueous solution of Cu, Co and Mn acetates as transition metal sources via sol-gel process and supercritical drying （SCD） technique. The effect of synthesis conditions on gelation was investigated. Moreover, the composition of the CuO-CoO-MnO/SiO2 nanocomposite aerogels was characterized by electron dispersive spectroscopy （EDS） and X-ray photoelectron spectroscopy （XPS）, and the specific surface area of the nanocomposite aerogels was determined by the Brunauer-Emmett-Teller （BET） method. Diphenyl carbonate （DPC） as the product was analyzed by gas chromatography （GC）. The experimental results show that the range of optimal temperature for gelation is 30-45 ℃, and the pH is 3.0-4.5. CuO-CoO-MnO/SiO2 nanocomposite aerogels are porous with a specific surface area of 384.9-700.6 m2/g. Compared to CO2 SCD, ethanol SCD is even favorable to the formation of aerogel with high specific surface area. The transition metals content in the nanocomposite aerogels can be controlled to be 0.71at%-13.77at%. With CuO-CoO-MnO/SiO2 nanocomposite aerogels as catalyst carrier, the yield of DPC is in direct proportion to the atomic fraction of transition metals in the nanocomposite aerogels, and it is up to 26.31 mass%, which is much higher than that via other porous carriers.
文摘Recently,methane of possible abiogenic origin has been reported from many localities within the Earth’s crust.However,little is known about the mechanisms of abiogenic methane formation during such processes.The Fischer-Tropsch reaction as a well known process for converting CO<sub>2</sub> to hydrocarbon gas by reaction with H<sub>2</sub> may take place on a metallic iron or iron oxide catalyst and also may take place on
基金supported by the National Natural Science Foundation of China(20590360)New Century Excellent Talent Project of China(NCET-05-0783)
文摘The effects of CeO2 contents and silica carrier porosity with their pore diameters ranging from 5.2 nm to 12.5 nm of CuO-CeO2/SiO2 cata-lysts in CO oxidation were investigated.The catalysts were characterized by N2 adsorption/desorption at low temperature,X-ray diffraction （XRD）,temperature-programmed reduction by H2 （H2-TPR）,oxygen temperature programmed desorption （O2-TPD） and X-ray photoelectron spectroscopy （XPS）.The results suggested that,the ceria content and the porosity of SiO2 carrier possessed great impacts on the structures and catalytic performances of CuO-CeO2/SiO2 catalysts.When appropriate content of CeO2 （Ce content 8 wt%） was added,the catalytic activity was greatly enhanced.In the catalyst supported on silica carrier with larger pore diameter,higher dispersion of CuO was observed,better agglomeration-resistant capacity was displayed and more lattice oxygen could be found,thus the CuO-CeO2 supported on Si-1 showed higher catalytic activity for low-temperature CO oxidation.
基金The Innovation Foundation of the Ministry of Science and Technology of China (No. 03C26213200932)the Natural Science Foundation of Henan Province (No.0624720029).
文摘The K2Ti4O9 whiskers were chosen for the catalyst carrier, TiO2/potassium titanate photocatalyst was prepared by Sol-gel method. The product was characterated by X-ray diffraction and SEM. EDS shows that, the main peck included Ti, O, and K in potassium titanate whisker. The main peak of K disappeared and the peaks of Ti, O stayed after whisker was covered. It directed that the surface of sample was covered by TiO2. XRD shows that diffraction peak appeared, which was corresponded to the peak of anatase TiO2. In the reaction device of photochemistry, using middle-pressure mercury lamp as illumination, rhodamine B as simulant pollutant, the photocatalytic performance of TiO2/potassium titanate was studied. Under the same conditions, the lower pH, the larger illuminance, the higher temperature, the greater aeration quantum and the lower initial concentration of rhodamine B, the higher decoloration rate was got. Under our experiment conditions: pH 6, the illuminance of 250W, the temperature of 313K, and the aeration quantum of 2.0L/min. When the concentration of rhodamine B was 8mg/L The photocatalyst of TiO2/potassium titanate was 0.01g/L. The decoloration rate of TiO2/potassium titanate dealt with the rhodamine B reach over 95% in 160min, and compare with TiO2, the decoloration rate of rhodamine B was improved 0.50~1.91 multiple. TiO2/potassium titanate can be used to treatment of dye wastewater.
基金supported by the National Natural Science Foundation of China(NSFC 20776089)the 985 Project of Sichuan University
文摘The catalytic performances of Co3O4/SiO2 catalysts prepared by incipient wetness impregnation for CO oxidation were investigated using three kinds of silica as carriers with different pore sizes of 7.7,14.0 and 27.0 nm.The effects of calcination temperature on the catalyst surface and micro structure properties as well as catalytic performance for the oxidation of carbon monoxide were also studied.All catalysts were characterized by N2 adsorption-desorption,XRD,XPS,FTIR,H2-TPR and O2-TPD.It was found that the properties and crystal size of cobalt-containing species strongly depended on the pore size of silica carrier.While the silica pore size increased from 7.7 to 27.0 nm,the Co3O4 crystal size increased from 8.5 to 13.5 nm.Moreover,it was demonstrated that if the spinel crystal structure of Co3O4 was obtained at a calcination temperature as low as 150℃,the catalyst sample would have a high Co3O4 surface dispersion and an increase of surface active species,and thus exhibit a high activity for the oxidation of carbon monoxide.
文摘This paper describes the influences of active metal, promoter and chelating agent on the properties of hydro-desulfuri-zationcatalyst. The use of chelating agent, especially its combination with common promoters e.g., EDTA-P, has an important meaning to develop highly active catalyst, specifically to unify the active metal dispersion degree and sulfurization degree in some extent, however, they are contradictory in conventional cognition. In the aspect of carriers, composition and nanometer carriers have more excellent performances in acidity, pores structureand metal-carrier interaction than common carriers, and are the developing trend in the future and should be a breakthrough mainly in preparation methods. We also pointed out the decisive factors to improve the activity of the catalyst: higher sulfurization degree of active metal oxide and higher aspect ratios of active phase crystal morphology, and the proper acidity and pores structure can be considered the key factors for deep desulfurization whose mainly obstacle is the desulfurization of large rigid molecules, e.g., dibenzothiophene and 4, 6-dimethyl substituted dibenzothiophene. Based on above that, We discussed the suitable hydrodesulfurization (HDS) catalyst for coal tar, aiming at providing some theoretical guidance for the “design” of coal tar HDS catalyst.
基金国家自然科学基金资助项目(22072172)国家杰出青年科学基金资助项目(21825204)+2 种基金中国科学院青年创新促进会资助项目(Y2021056)榆林学院与大连清洁能源国家实验室合作基金资助项目(YLU-DNL Fund 2022007)山西省科技创新团队专项资金资助项目(202304051001007)。
