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磷改性β沸石作为活性组分对FCC催化剂性能的影响 被引量:2
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作者 谢传欣 赵静 +1 位作者 潘惠芳 宁顺康 《石油化工》 CAS CSCD 北大核心 2002年第9期691-695,共5页
以磷改性β沸石替代质量分数5%的USY沸石作为流化催化裂化(FCC)模式催化剂的活性组分,通过实验室轻油微反、固定-流化床装置评价其催化性能。结果说明,FCC催化剂中加入一定量磷改性β沸石可以提高原料油的转化率、降低催化剂的比积碳及... 以磷改性β沸石替代质量分数5%的USY沸石作为流化催化裂化(FCC)模式催化剂的活性组分,通过实验室轻油微反、固定-流化床装置评价其催化性能。结果说明,FCC催化剂中加入一定量磷改性β沸石可以提高原料油的转化率、降低催化剂的比积碳及催化裂化汽油的烯烃含量。针对不同的原料油,汽油研究法辛烷值有不同程度的提高。 展开更多
关键词 磷改性β沸石 活性组分 FCC催化剂 性能 影响 催化裂化 比积碳 模式催化剂 轻油微反 固定-流化床
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Chemical vapor deposition of SiC at different molar ratios of hydrogen to methyltrichlorosilane 被引量:1
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作者 杨艳 张伟刚 《Journal of Central South University》 SCIE EI CAS 2009年第5期730-737,共8页
Chemical vapor deposition(CVD) of SiC from methyltrichlorosilane(MTS) was studied at two different molar ratios of H2 to MTS(n(H2) /n(MTS) ) . The total pressure was kept as 100 kPa and the temperature was varied from... Chemical vapor deposition(CVD) of SiC from methyltrichlorosilane(MTS) was studied at two different molar ratios of H2 to MTS(n(H2) /n(MTS) ) . The total pressure was kept as 100 kPa and the temperature was varied from 850 to 1 100 ℃ at a total residence time of 1 s. Steady-state deposition rates as functions of reactor length and of temperature,investigated at different n(H2) /n(MTS) values,show that hydrogen exhibits strongly influences on the deposition rate. Especially,the deposition of Si co-deposit can be obtained in broader substrate length and at higher temperatures with increasing hydrogen partial pressure. Influence of hydrogen on the deposition process was also studied using gas phase composition and deposit composition analysis at various n(H2) /n(MTS) . SEM micrographs directly show the variation of surface morphologies at various n(H2) /n(MTS) . It can be found that the crystal grain of the deposit at 1 100 ℃ is better developed and the crystallization is also improved with increasing n(H2) /n(MTS) . 展开更多
关键词 METHYLTRICHLOROSILANE silicon carbide H2 MTS
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Fibrous activated alumina prepared through phase transformation using dawsonite as a template 被引量:2
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作者 TANG Jie LIU Gui-hua +3 位作者 QI Tian-gui ZHOU Qiu-sheng PENG Zhi-hong LI Xiao-bin 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第4期1147-1160,共14页
Fibrous activated alumina is widely applied in catalysts,adsorbents,and composite materials.This work presents a green approach in preparing the fibrous activated Al_(2)O_(3) with high purity and specific surface area... Fibrous activated alumina is widely applied in catalysts,adsorbents,and composite materials.This work presents a green approach in preparing the fibrous activated Al_(2)O_(3) with high purity and specific surface area through multistep phase transformation of aluminum-bearing substances using intermediate dawsonite as a template.Thermodynamic calculations and experimental results show that increasing the concentration of Na_(2)CO_(3) and(NH_(4))_(2)CO_(3) is remarkably beneficial to the formation of dawsonite and ammonium aluminum carbonate hydroxide,respectively.Based on determination of dissolution and precipitation mechanism,the ultrafine granular gibbsite is converted to the uniform fibrous dawsonite with a ratio of length to diameter over 50,and the fibrous dawsonite changes into the long fibrous ammonium aluminum carbonate hydroxide with a ratio of length to diameter is about 80 in above 70 g/L(NH_(4))_(2)CO_(3) solution.Furthermore,the activated alumina remains fibrous morphology after roasting ammonium aluminum carbonate hydroxide at a slow heating rate,plentiful open mesopore and weak aggregation of particles,which contributes to the high specific surface area of 159.37 m^(2)/g at 1273 K for the activated alumina.The complete transformation of dawsonite to ammonium aluminum carbonate hydroxide and high specific surface area contribute to the purity of the activated fibrous alumina above 99.9%with low Na and Fe content. 展开更多
关键词 fibers activated alumina specific surface area DAWSONITE ammonium aluminum carbonate hydroxide
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Novel synthesis of nickel oxide microsphere with high surface area and its catalytic application for carbon dioxide reforming of methane
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作者 吴旭 武正簧 +1 位作者 安霞 谢鲜梅 《Journal of Central South University》 SCIE EI CAS 2014年第5期1747-1751,共5页
Nickel oxide(NiO)microsphere with a large surface area was novelly synthesized through nickel bicarbonate(Ni(HCO3)2)precursor.The obtained nickel oxide(NiO)microsphere was characterized by X-ray pattern diffraction,sc... Nickel oxide(NiO)microsphere with a large surface area was novelly synthesized through nickel bicarbonate(Ni(HCO3)2)precursor.The obtained nickel oxide(NiO)microsphere was characterized by X-ray pattern diffraction,scanning electron microscopy,CO2 temperature-programmed desorption,H2 temperature-programmed reduction,N2 adsorption/desorption and laser scattering particle size distribution analyzer.It was found that nickel oxide(NiO)synthesized by the thermal decomposition of Ni(HCO3)2through area hydrolysis,presented very nice microsphere with high surface area.The catalytic properties of obtained nickel oxide(NiO)microsphere were studied in the reaction of carbon dioxide reforming of methane where 91.3% conversion of CH4 with 93% conversion of CO2 was observed.Besides,the catalyst maintained high stability over 200 h on the stream. 展开更多
关键词 SYNTHESIS NiO microsphere large surface area CATALYSIS
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Adsorption of Cholesterol on Carbon Powders
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作者 Jennifer Lee Gordon Thomas Roy Rybolt Christina Elizabeth Wells 《Journal of Chemistry and Chemical Engineering》 2010年第9期14-27,共14页
Carbon powders have the ability to remove cholesterol from solution by adsorption. Various combinations from among 12 different types of carbon powders (including two medical carbons), having a wide range of surface... Carbon powders have the ability to remove cholesterol from solution by adsorption. Various combinations from among 12 different types of carbon powders (including two medical carbons), having a wide range of surface area and porosity, were used to perform cholesterol adsorption experiments. The cholesterol concentration in a cyclohexane solvent (37 ~C, shaking 200 rpm) was detected at 215 nm using ultraviolet spectroscopy. Most adsorption occurred in the first 30 to 60 minutes. A Langmuir model was used to fit the amount of cholesterol adsorbed per gram of carbon. The medical carbon, Natural Elements Activated Charcoal, adsorbed 234 mg of cholesterol adsorption per gram of carbon. The experimental percentages of cholesterol removed from solution (maximum 98%) were correlated with nitrogen Branauer-Emmett-Teller (BET) surface areas and micro, meso, and macropore volume distributions. Surface area alone was not a suitable predictor of cholesterol adsorption. However, carbon powders exhibiting a large surface area along with significant meso and macropores were shown to be effective in adsorbing cholesterol from a nonpolar environment. Ingestion of a medically approved carbon powder with a large surface area and sufficient meso and macroporosity may be able to adsorb cholesterol in the intestinal tract and thereby lower cholesterol levels in the body. 展开更多
关键词 CHOLESTEROL adsorption capacity adsorption from solution Langmuir isotherm enterosorption POROSITY BET surface area carbon powder.
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What are the practical limits for the specific surface area and capacitance of bulk sp^2 carbon materials? 被引量:1
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作者 Yanhong Lu Guankui Long +6 位作者 Long Zhang Tengfei Zhang Mingtao Zhang Fan Zhang Yang Yang Yanfeng Ma Yongsheng Chen 《Science China Chemistry》 SCIE EI CAS CSCD 2016年第2期225-230,共6页
The possible practical limits for the specific surface area and capacitance performance of bulk sp^2 carbon materials were investigated experimentally and theoretically using a variety of carbon materials. We find the... The possible practical limits for the specific surface area and capacitance performance of bulk sp^2 carbon materials were investigated experimentally and theoretically using a variety of carbon materials. We find the limit for the specific surface area to be 3500–3700 m^2 g^(-1), and based on this, the corresponding best capacitance was predicted for various electrolyte systems. A model using an effective ionic diameter for the electrolyte ions was proposed and used to calculate the theoretical capacitance. A linear dependence of experimental capacitance versus effective specific surface area of various sp^2 carbon materials was obtained for all studied ionic liquid, organic and aqueous electrolyte systems. Furthermore, excellent agreement between the theoretical and experimental capacitance was observed for all the tested sp^2 carbon materials in these electrolyte systems, indicating that this model can be applied widely in the evaluation of various carbon materials for supercapacitors. 展开更多
关键词 GRAPHENE bulk sp2 carbon materials SUPERCAPACITOR specific surface area DFT modeling
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Sulfur/nickel ferrite composite as cathode with high-volumetric-capacity for lithium-sulfur battery 被引量:13
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作者 Ze Zhang Di—Hua Wu +2 位作者 Zhen Zhou Guo—Ran Li Sheng Liu and Xue—Ping Gao 《Science China Materials》 SCIE EI CSCD 2019年第1期74-86,共13页
Low volumetric energy density is a bottleneck for the application of lithium-sulfur (Li-S)battery.The low- density sulfur cooperated with the light-weight carbon sub- strate realizes electrochemical cycle stability,bu... Low volumetric energy density is a bottleneck for the application of lithium-sulfur (Li-S)battery.The low- density sulfur cooperated with the light-weight carbon sub- strate realizes electrochemical cycle stability,but leads to worse volumetric energy density.Here,nickel ferrite (NiFe2O4)nanofibers as novel substrate for sulfur not only anchor lithium polysulfides to enhance the cycle stability of sulfur cathode,but also contribute to the high volumetric capacity of the S/nickel ferrite composite.Specifically,the S/ nickel ferrite composite presents an initial volumetric capacity of 1,281.7mA h cm^-3-composite at 0.1C rate,1.9times higher than that of S/carbon nanotubes,due to the high tap density of the S/nickel ferrite composite. 展开更多
关键词 lithium-sulfur battery sulfur cathode nickel ferrite nanofibers tap density volumetric capacity
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