The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform
Jinlin Li - One of the best experts on this subject based on the ideXlab platform.
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Novel Bi2O3/NaBi(MoO4)2 heterojunction with enhanced photocatalytic activity under visible light irradiation
Journal of Alloys and Compounds, 2013Co-Authors: Juncheng Hu, Lizhong Li, Jinlin LiAbstract:A novel Bi2O3/NaBi(MoO4)2 composite photocatalyst with nanostructured heterojunctions was prepared via a simple Supercritical Method. The products were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and UV–vis diffuse reflectance spectroscopy (DRS). The visible light-induced photocatalytic activities were evaluated. The activity of the composite catalyst was 5 and 13 times as much as that of pure NaBi(MoO4)2 and commercial Bi2O3, respectively. The catalyst could be reused more than five times without obvious deactivation. The enhanced photocatalytic performance was attributed to electric-field-assisted charge transfer at the heterojunction interfaces between Bi2O3 and NaBi(MoO4)2 with matching band potentials, which consequently favored an effective photoexcited electron and hole separation.
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Novel Bi2O3/NaBi(MoO4)2 Heterojunction with Enhanced Photocatalytic Activity under Visible Light Irradiation.
ChemInform, 2013Co-Authors: Juncheng Hu, Lizhong Li, Jinlin LiAbstract:The Bi2O3/NaBi(MoO4)2 composite photocatalyst with nanostructured heterojunctions is prepared by a Supercritical Method employing Bi(NO3)3 and NaMoO4 solutions in EtOH to which citric acid is added (Bi/Mo ratio of 1.33, autoclave, 1 MPa of N2, 243 °C, 4 h).
Juncheng Hu - One of the best experts on this subject based on the ideXlab platform.
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Novel Bi2O3/NaBi(MoO4)2 heterojunction with enhanced photocatalytic activity under visible light irradiation
Journal of Alloys and Compounds, 2013Co-Authors: Juncheng Hu, Lizhong Li, Jinlin LiAbstract:A novel Bi2O3/NaBi(MoO4)2 composite photocatalyst with nanostructured heterojunctions was prepared via a simple Supercritical Method. The products were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and UV–vis diffuse reflectance spectroscopy (DRS). The visible light-induced photocatalytic activities were evaluated. The activity of the composite catalyst was 5 and 13 times as much as that of pure NaBi(MoO4)2 and commercial Bi2O3, respectively. The catalyst could be reused more than five times without obvious deactivation. The enhanced photocatalytic performance was attributed to electric-field-assisted charge transfer at the heterojunction interfaces between Bi2O3 and NaBi(MoO4)2 with matching band potentials, which consequently favored an effective photoexcited electron and hole separation.
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Novel Bi2O3/NaBi(MoO4)2 Heterojunction with Enhanced Photocatalytic Activity under Visible Light Irradiation.
ChemInform, 2013Co-Authors: Juncheng Hu, Lizhong Li, Jinlin LiAbstract:The Bi2O3/NaBi(MoO4)2 composite photocatalyst with nanostructured heterojunctions is prepared by a Supercritical Method employing Bi(NO3)3 and NaMoO4 solutions in EtOH to which citric acid is added (Bi/Mo ratio of 1.33, autoclave, 1 MPa of N2, 243 °C, 4 h).
Shiro Saka - One of the best experts on this subject based on the ideXlab platform.
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Reactivity of Triglycerides and Fatty Acids in Sub/Supercritical Dialkyl Carbonates for Biodiesel Production
Zero-Carbon Energy Kyoto 2012, 2013Co-Authors: Zul Ilham, Shiro SakaAbstract:Recently, interest in dialkyl carbonates as an environmentally benign chemical for green chemistry is increasing but its utilization for biodiesel production in non-catalytic Supercritical Method has never been discussed earlier. Therefore, we studied the reactivity of triglycerides and fatty acids with several dialkyl carbonates in the non-catalytic sub/Supercritical treatment in order to evaluate the potential of various dialkyl carbonates for the production of fatty acid alkyl esters (FAAE) and other value-added by-products. In batch-type and flow-type reaction systems, reaction condition was set at 300°C/20 MPa when dimethyl carbonate, diethyl carbonate, dipropyl carbonate and dibutyl carbonate have been utilized as reactants. The results showed that esterification of fatty acids proceeds at higher reaction rate than the interesterification of triglycerides in non-catalytic Supercritical dialkyl carbonates. Shorter alkyl chains of dialkyl carbonates also showed higher reactivity than the longer ones. Based on the obtained results, potential of dialkyl carbonates for biodiesel production in non-catalytic Supercritical process was discussed.
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dimethyl carbonate as potential reactant in non catalytic biodiesel production by Supercritical Method
Bioresource Technology, 2009Co-Authors: Zul Ilham, Shiro SakaAbstract:Abstract In this study, the non-catalytic Supercritical Method has been studied in utilizing dimethyl carbonate. It was demonstrated that, the Supercritical dimethyl carbonate process without any catalysts applied, converted triglycerides to fatty acid methyl esters with glycerol carbonate and citramalic acid as by-products, while free fatty acids were converted to fatty acid methyl esters with glyoxal. After 12 min of reaction at 350 °C/20 MPa, rapeseed oil treated with Supercritical dimethyl carbonate reached 94% (w/w) yield of fatty acid methyl ester. The by-products from this process which are glycerol carbonate and citramalic acid are much higher in value than glycerol produced by the conventional process. In addition, the yield of the fatty acid methyl esters as biodiesel was almost at par with Supercritical methanol Method. Therefore, Supercritical dimethyl carbonate process can be a good candidate as an alternative biodiesel production process.
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Biodiesel production by Supercritical process with crude bio-methanol prepared by wood gasification.
Bioresource Technology, 2007Co-Authors: Yohei Isayama, Shiro SakaAbstract:In order to prepare a genuine biodiesel, it is essential to use methanol prepared from biomass but not natural gas for biodiesel production. Thus, we have proposed to use crude bio-methanol produced by wood gasification for biodiesel production. Since such a bio-methanol contains some impurities, an effect of its impurities was studied on the biodiesel production by Supercritical Method. In general, impurities in crude bio-methanol are reported to include methyl formate, ethanol, 1-butanol, diisopropyl ether, water, etc. Triglycerides and oleic acids were, thus, treated with these impurities under Supercritical conditions. As a result, it was found that methyl formate, ethanol and 1-butanol could convert them to fatty acid alkyl esters (BDF), whereas no conversion was achieved with diisopropyl ether. Thus, crude bio-methanol can be used for BDF production as a substitute for methanol from fossil resources. However, due to more efficient reaction, crude bio-methanol can be more applicable to the two-step Supercritical methanol process, consisting of hydrolysis of triglycerides and subsequent esterification of fatty acids, compared with the one-step Supercritical methanol process, where transesterification of triglycerides is a major reaction.
Alain Pierre - One of the best experts on this subject based on the ideXlab platform.
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NMR and IR spectroscopy of silica aerogels with different hydrophobic characteristics
Journal of Non-crystalline Solids, 2005Co-Authors: H. El Rassy, Alain PierreAbstract:Abstract Silica aerogels, prepared by the sol–gel Method and dried by the CO2 Supercritical Method, were produced from tetramethoxysilane (TMOS) and methyltrimethoxysilane (MTMS) in different proportions, in order to change the proportions of hydrophilic and hydrophobic surface groups. The aerogel hydrophobic or hydrophilic properties were related to their surface structural characteristics. The relative proportion of Si–OH, Si–OCH3 or Si–CH3 groups present on the aerogel pore surface and its silica network structure were determined by 1H, 29Si and 13C nuclear magnetic resonance (NMR). The results obtained were correlated with the infrared transmission spectra. From these data, a possible description of the mixed hydrophilic–hydrophobic nature of the surface of these materials is proposed.
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Surface Characterization of Silica Aerogels with Different Proportions of Hydrophobic Groups, Dried by the CO2 Supercritical Method
Langmuir, 2003Co-Authors: H. El Rassy, Paulette Buisson, B. Bouali, And A. Perrard, Alain PierreAbstract:Silica aerogels, dried by the CO2 Supercritical Method, were made from tetramethoxysilane (TMOS) and methyltrimethoxylsilane (MTMS) in different proportions to change the proportions of hydrophilic and hydrophobic surface groups. The aerogel hydrophobic or hydrophilic properties were related to their textural and surface structural characteristics. In particular, water adsorption isotherms were recorded by successive equilibrium with saturated aqueous metal salt solutions. They were compared to nitrogen adsorption isotherms. The relative proportion of Si−OH, Si−OCH3, or Si−CH3 end groups present on the gel surface was determined by nuclear magnetic resonance (NMR) of 1H. The results obtained were correlated with measurements of the contact angle with water, after equilibration of the gels at various water activity. From these data, a possible description of the mixed hydrophilic−hydrophobic nature of the surface of these materials is finally proposed.
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Catalytic activity of Burkholderia (Pseudomonas) cepacia encapsulated in silica aerogels in esterification and hydrolysis as a function of the gel and solvent hydrophobicities
Journal of Molecular Catalysis B-enzymatic, 2002Co-Authors: S. Maury, Paulette Buisson, Alain PierreAbstract:Lipase from Burkholderia (formerly Pseudomonas) cepacia was encapsulated in silica aerogels dried by the Supercritical Method with CO2. Aerogels with hydrophilic and hydrophobic functionalities were made by combining different proportions of tetramethoxysilane and methyltrimethosysilane as the silicon precursors. These aerogels were tested in the esterification of lauric acid by 1-octanol, as well as in the hydrolysis reaction of octyl laurate. These catalytic tests were carried out in two different solvents, namely water saturated isooctane or dioxane containing different initial water concentrations. The adsorption of the esterification and hydrolysis reactants, taken separately, on the most active aerogel in water saturated isooctane was studied. The results showed that for esterification as well as for hydrolysis, the most active gels were the hydrophobic ones, independent of the solvent or water proportion used. Esterification reaction was much faster in water saturated isooctane, whereas hydrolysis was favored in dioxane, with the highest water concentration, as expected from the thermodynamics. As for the adsorption results, they showed that the reactant most taken by the gel is lauric acid. This study showed that the acid is not only adsorbed, but seems to undergo a reaction with the gel.
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Encapsulation of lipases in aerogels
Journal of Non-crystalline Solids, 2001Co-Authors: Paulette Buisson, C Hernandez, M Pierre, Alain PierreAbstract:Abstract Pseudomonas cepacia (PC) lipase was encapsulated in silica and aluminosilicate gels made by different chemical processes. Some samples were dried by the Supercritical Method in CO 2 to obtain aerogels, while other ones made by the same wet chemical procedure were dried by evaporation to produce xerogels. The biocatalysts which were obtained were compared in the esterification reaction of 1-octanol by lauric acid. In all cases, the aerogels performed better than the corresponding xerogels. This biocatalysis behavior is discussed in relationship with the textural and structural characteristics of the gels, studied by nitrogen sorption, 29 Si NMR and 27 Al NMR. It is proposed that Supercritical drying avoids a simultaneous compression of the gel network and of the enzyme, hence improving the biocatalytic activity.
Lizhong Li - One of the best experts on this subject based on the ideXlab platform.
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Novel Bi2O3/NaBi(MoO4)2 heterojunction with enhanced photocatalytic activity under visible light irradiation
Journal of Alloys and Compounds, 2013Co-Authors: Juncheng Hu, Lizhong Li, Jinlin LiAbstract:A novel Bi2O3/NaBi(MoO4)2 composite photocatalyst with nanostructured heterojunctions was prepared via a simple Supercritical Method. The products were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and UV–vis diffuse reflectance spectroscopy (DRS). The visible light-induced photocatalytic activities were evaluated. The activity of the composite catalyst was 5 and 13 times as much as that of pure NaBi(MoO4)2 and commercial Bi2O3, respectively. The catalyst could be reused more than five times without obvious deactivation. The enhanced photocatalytic performance was attributed to electric-field-assisted charge transfer at the heterojunction interfaces between Bi2O3 and NaBi(MoO4)2 with matching band potentials, which consequently favored an effective photoexcited electron and hole separation.
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Novel Bi2O3/NaBi(MoO4)2 Heterojunction with Enhanced Photocatalytic Activity under Visible Light Irradiation.
ChemInform, 2013Co-Authors: Juncheng Hu, Lizhong Li, Jinlin LiAbstract:The Bi2O3/NaBi(MoO4)2 composite photocatalyst with nanostructured heterojunctions is prepared by a Supercritical Method employing Bi(NO3)3 and NaMoO4 solutions in EtOH to which citric acid is added (Bi/Mo ratio of 1.33, autoclave, 1 MPa of N2, 243 °C, 4 h).