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Jianyi Shen - One of the best experts on this subject based on the ideXlab platform.
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effect of Surface Acidity basicity on the selective hydrogenation of maleic anhydride to succinic anhydride over supported nickel catalysts
Catalysis Communications, 2018Co-Authors: Jingxuan Cai, Jianxin Zhu, Li Zuo, Jianyi ShenAbstract:Abstract The catalysts 60%Ni/Al2O3, 60%Ni/MgAlO and 60%Ni/MgO were prepared and used for the hydrogenation of maleic anhydride (MA) to succinic anhydride (SA). Characterization results showed that Ni particles were highly dispersed in the catalysts so that they possessed the high density of active Ni sites, and thus the high activities for the reaction. In particular, it was found that the Surface Acidity favored the conversion of MA on Ni, but was unfavorable for the selectivity to SA, while the Surface basicity played the opposite role. The Ni/MgAlO exhibited the proper Acidity and basicity and thus the excellent performance for the reaction.
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effect of acidic promoters on the titania nanotubes supported v2o5 catalysts for the selective oxidation of methanol to dimethoxymethane
Chinese Journal of Catalysis, 2013Co-Authors: Jingxuan Cai, Qing Sun, Minhui Jia, Jianyi ShenAbstract:The effect of acidic promoters on the titania-nanotubes (TNT) supported V2O5 catalysts (VTNT) was investigated. The structure of TNT was quite stable after the treatment with sulfuric, phosphoric, and phosphotungstic acids, respectively. The acid-modified VTNT catalysts were tested for the selective oxidation of methanol to dimethoxymethane (DMM). It was found that only the VTNT modified with sulfuric acid followed by calcination at 673 K exhibited the significantly enhanced selectivity to DMM with high methanol conversions. The calcination created some sulfate groups strongly interacted with vanadium species, which enhanced the strengths of Surface Acidity without weakening the redox ability of vanadium sites. The addition of phosphoric and phosphotungstic acids might enhance the Surface Acidity of V2O5/TiO2, but weakened its redox ability, and therefore had the negative effect for the target reaction.
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selective oxidation of methanol to dimethoxymethane under mild conditions over v2o5 tio2 with enhanced Surface Acidity
Chemical Communications, 2007Co-Authors: Jianyi ShenAbstract:Dimethoxymethane was synthesized from the direct oxidation of methanol with high conversion and selectivity over specially designed bifunctional V2O5/TiO2 catalysts with redox and enhanced acidic character, in which the Surface Acidity played an essential role for inhibiting the formation of formaldehyde through the enhanced condensation reaction of formaldehyde with methanol to produce dimethoxymethane.
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Surface Acidity and basicity of γ al2o3 doped with k and la3 and calcined at elevated temperatures
Thermochimica Acta, 2003Co-Authors: Hu Zou, Jianyi ShenAbstract:Abstract High temperature reactions in industry require catalysts with high stability. Basic metal oxides, K2O and La2O3, were added to γ-Al2O3 in order to obtain supports with low Acidity and high Surface areas at high temperatures. Microcalorimetry and FT-IR were employed to determine the Surface Acidity and basicity using ammonia and carbon dioxide as the probe molecules. It was found that the addition of basic metal oxides inhibited the transformation of γ-Al2O3 to the forms such as θ-Al2O3 and α-Al2O3 when calcined at 1000 °C. Instead, X-ray diffraction (XRD) results indicated the formation of aluminates for the supported samples. The 6% K2O/γ-Al2O3 sample retained high Surface area of 188 m2 g−1 and strong basicity (170 kJ mol−1 for CO2 adsorption) when calcined at 600 °C. The sample retained the Surface area of about 100 m2 g−1 when calcined at 1000 °C. In this case, the sample possessed low Acidity and basicity and may be used as a neutral support with high thermal stability. The addition of La2O3 onto γ-Al2O3 might cause even more loss of Surface area when calcined at high temperatures. The formation of a perovskite phase LaAlO3 on the Surface of the La2O3/γ-Al2O3 samples calcined at 1000 °C led to the low Acidity and basicity.
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Surface Acidity basicity and catalytic reactivity of ceo2 al2o3 catalysts for the oxidative dehydrogenation of ethane with carbon dioxide to ethylene
2003Co-Authors: Qing Sun, Jianyi ShenAbstract:Dehydrogenation of ethane to ethylene in CO2 was investigated over CeO2/ -Al2O3 catalysts at 700 in a conventional o w reactor operating at atmospheric pressure. XRD, BET and microcalori- metric adsorption techniques were used to characterize the structure and Surface Acidity/basicity of the CeO2/ -Al2O3 catalysts. The results show that the Surface Acidity decreased while the Surface basicity increased after the addition of CeO2 to -Al2O3. Accordingly, the activity of the hydrogenation reaction of CO2 increased, which might be responsible for the enhanced conversion in the dehydrogenation of ethane to ethylene. The highest ethane conversion obtained was about 15% for the 25%CeO2/ -Al2O3. The selectivity to ethylene was high for all the CeO2, -Al2O3 and CeO2/ -Al2O3 catalysts.
In Kyu Song - One of the best experts on this subject based on the ideXlab platform.
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catalytic decomposition of benzyl phenyl ether to aromatics over cesium exchanged heteropolyacid catalyst
Korean Journal of Chemical Engineering, 2011Co-Authors: Hai Woong Park, Sunyoung Park, Dong Ryul Park, Jung Ho Choi, In Kyu SongAbstract:Cesium-exchanged Cs x H3.0−x PW12O40 (X=2.0–3.0) heteropolyacid catalysts were prepared and applied to the decomposition of benzyl phenyl ether to aromatics. Benzyl phenyl ether was chosen as a lignin model compound for representing α-O-4 bond in lignin. Phenol, benzene, and toluene were mainly produced by the decomposition of benzyl phenyl ether. Conversion of benzyl phenyl ether and total yield for main products (phenol, benzene, and toluene) were closely related to the Surface Acidity of Cs x H3.0−x PW12O40 (X=2.0–3.0) heteropolyacid catalyst. Conversion of benzyl phenyl ether and total yield for main products increased with increasing Surface Acidity of the catalyst. Among the catalysts tested, Cs2.5H0.5PW12O40 with the largest Surface Acidity showed the highest conversion of benzyl phenyl ether and total yield for main products.
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effect of divalent metal component meii on the catalytic performance of meiife2o4 catalysts in the oxidative dehydrogenation of n butene to 1 3 butadiene
Catalysis Letters, 2008Co-Authors: Howon Lee, Taejin Kim, Ji Chul Jung, Heesoo Kim, Youngmin Chung, Seong Jun Lee, Yong Seung Kim, In Kyu SongAbstract:A series of metal ferrite (MeIIFe2O4) catalysts were prepared by a co-precipitation method with a variation of divalent metal component (MeII = Zn, Mg, Mn, Ni, Co, and Cu) for use in the oxidative dehydrogenation of n-butene to 1,3-butadiene. Successful formation of metal ferrite catalysts with a random spinel structure was confirmed by XRD, ICP-AES, and XPS analyses. The catalytic performance of metal ferrite catalysts in the oxidative dehydrogenation of n-butene strongly depended on the identity of divalent metal component. Acid properties of metal ferrite catalysts were measured by NH3-TPD experiments, with an aim of correlating the catalytic performance with the acid property of the catalysts. It was revealed that the yield for 1,3-butadiene increased with increasing Surface Acidity of the catalyst. Among the catalysts tested, ZnFe2O4 catalyst with the largest Surface Acidity showed the best catalytic performance in the oxidative dehydrogenation of n-butene.
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effect of divalent metal component me ii on the catalytic performance of me ii fe 2 o 4 catalysts in the oxidative dehydrogenation of n butene to 1 3 butadiene
Catalysis Letters, 2008Co-Authors: Howon Lee, Taejin Kim, Ji Chul Jung, Heesoo Kim, Youngmin Chung, Seong Jun Lee, Yong Seung Kim, In Kyu SongAbstract:A series of metal ferrite (MeIIFe2O4) catalysts were prepared by a co-precipitation method with a variation of divalent metal component (MeII = Zn, Mg, Mn, Ni, Co, and Cu) for use in the oxidative dehydrogenation of n-butene to 1,3-butadiene. Successful formation of metal ferrite catalysts with a random spinel structure was confirmed by XRD, ICP-AES, and XPS analyses. The catalytic performance of metal ferrite catalysts in the oxidative dehydrogenation of n-butene strongly depended on the identity of divalent metal component. Acid properties of metal ferrite catalysts were measured by NH3-TPD experiments, with an aim of correlating the catalytic performance with the acid property of the catalysts. It was revealed that the yield for 1,3-butadiene increased with increasing Surface Acidity of the catalyst. Among the catalysts tested, ZnFe2O4 catalyst with the largest Surface Acidity showed the best catalytic performance in the oxidative dehydrogenation of n-butene.
Zifeng Yan - One of the best experts on this subject based on the ideXlab platform.
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zeolite y mother liquor modified γ al2o3 with enhanced bronsted Acidity as active matrix to improve the performance of fluid catalytic cracking catalyst
Industrial & Engineering Chemistry Research, 2018Co-Authors: Peng Bai, Ke Qiao, Youhe Wang, Mengjie Xie, U J Etim, Wei Xing, Yanan Zhang, Bowen Liu, Zifeng YanAbstract:A new matrix material for the fluid catalytic cracking (FCC) catalyst was prepared using the zeolite Y mother liquor to modify the Surface Acidity of γ-Al2O3. The modified γ-Al2O3 was characterized using a variety of techniques, and the relationship between Surface Acidity and catalytic performances in the catalytic cracking of vacuum gas oil (VGO) was correlated. Characterization results showed that Bronsted acid sites derived mainly from isolated silanol groups, which increased on modified γ-Al2O3, while Lewis acid sites reduced dramatically after modification. Correlation results indicated that increased Bronsted acid sites effectively improved the conversion of VGO. In addition, new medium strong acid sites engendered at the interfaces of γ-Al2O3/amorphous silica–alumina or γ-Al2O3/zeolite Y played a critical role in determining the final product distribution, leading to yields of gasoline and liquefied petroleum gas higher than those of the pure γ-Al2O3 derived catalyst.
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preparation and characterization of γ al2o3 with rich bronsted acid sites and its application in the fluid catalytic cracking process
Journal of Physical Chemistry C, 2014Co-Authors: Rui Feng, Peng Bai, Songtao Liu, Ke Qiao, Youhe Wang, Hamid Almegren, Mark J Rood, Zifeng YanAbstract:The objective of this work is to investigate the Surface Acidity of γ-Al2O3 after modification and its application in reducing coke formation in the fluid catalytic cracking (FCC) process. γ-Al2O3 with rich Bronsted acid sites and reduced Lewis acid sites was prepared by the sol–gel method using NH4BF4 as a modifier to develop a new functional material to adjust Surface Acidity. N2 sorption, powder X-ray diffraction (XRD), 27Al magic angle spinning nuclear magnetic resonance (27Al MAS NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) spectroscopy were used to characterize the structure and Surface properties of the prepared γ-Al2O3. The results showed that partial fluorination of the Surface of γ-Al2O3 generated small quantities of a pyrochlore-type phase which was formed mainly by substitution of the OH group on six-coordinated aluminum with fluorine. In addition, boron insertion in the structure of γ-Al2O3 reduced the Lewis acid concentration and increased...
Taejin Kim - One of the best experts on this subject based on the ideXlab platform.
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effect of divalent metal component me ii on the catalytic performance of me ii fe 2 o 4 catalysts in the oxidative dehydrogenation of n butene to 1 3 butadiene
Catalysis Letters, 2008Co-Authors: Howon Lee, Taejin Kim, Ji Chul Jung, Heesoo Kim, Youngmin Chung, Seong Jun Lee, Yong Seung Kim, In Kyu SongAbstract:A series of metal ferrite (MeIIFe2O4) catalysts were prepared by a co-precipitation method with a variation of divalent metal component (MeII = Zn, Mg, Mn, Ni, Co, and Cu) for use in the oxidative dehydrogenation of n-butene to 1,3-butadiene. Successful formation of metal ferrite catalysts with a random spinel structure was confirmed by XRD, ICP-AES, and XPS analyses. The catalytic performance of metal ferrite catalysts in the oxidative dehydrogenation of n-butene strongly depended on the identity of divalent metal component. Acid properties of metal ferrite catalysts were measured by NH3-TPD experiments, with an aim of correlating the catalytic performance with the acid property of the catalysts. It was revealed that the yield for 1,3-butadiene increased with increasing Surface Acidity of the catalyst. Among the catalysts tested, ZnFe2O4 catalyst with the largest Surface Acidity showed the best catalytic performance in the oxidative dehydrogenation of n-butene.
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effect of divalent metal component meii on the catalytic performance of meiife2o4 catalysts in the oxidative dehydrogenation of n butene to 1 3 butadiene
Catalysis Letters, 2008Co-Authors: Howon Lee, Taejin Kim, Ji Chul Jung, Heesoo Kim, Youngmin Chung, Seong Jun Lee, Yong Seung Kim, In Kyu SongAbstract:A series of metal ferrite (MeIIFe2O4) catalysts were prepared by a co-precipitation method with a variation of divalent metal component (MeII = Zn, Mg, Mn, Ni, Co, and Cu) for use in the oxidative dehydrogenation of n-butene to 1,3-butadiene. Successful formation of metal ferrite catalysts with a random spinel structure was confirmed by XRD, ICP-AES, and XPS analyses. The catalytic performance of metal ferrite catalysts in the oxidative dehydrogenation of n-butene strongly depended on the identity of divalent metal component. Acid properties of metal ferrite catalysts were measured by NH3-TPD experiments, with an aim of correlating the catalytic performance with the acid property of the catalysts. It was revealed that the yield for 1,3-butadiene increased with increasing Surface Acidity of the catalyst. Among the catalysts tested, ZnFe2O4 catalyst with the largest Surface Acidity showed the best catalytic performance in the oxidative dehydrogenation of n-butene.
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molecular electronic structure Surface Acidity relationships of model supported tungsten oxide catalysts
Journal of Catalysis, 2007Co-Authors: Taejin Kim, Andrew Burrows, Christopher J. Kiely, Israel E. WachsAbstract:A series of model-supported WO3 catalysts were synthesized on preformed Al2O3, Nb2O5, TiO2, and ZrO2 supports by impregnation of aqueous ammonium metatungstate, (NH4)10W12O41⋅5H2O. The molecular and electronic structures of the supported tungsten oxide phases were determined with in situ Raman and UV–vis spectroscopy, respectively. The supported tungsten oxide structures are the same on all oxide supports as a function of tungsten oxide Surface density (W/nm2). Below monolayer coverage ( 5 W/nm2), crystalline WO3 nanoparticles are present on top of the Surface WOx monolayer. Above ∼10 W/nm2, bulk-like WO3 crystallites become dominant. The number of catalytic active sites and Surface chemistry of the supported tungsten oxide phases were chemically probed with CH3OH dehydration to CH3OCH3. The specific oxide support was found to significantly affect the relative catalytic Acidity of the Surface WOx species (Al2O3 ≫ TiO2 > Nb2O5 > ZrO2) to that of the supported WO3 nanoparticles. Consequently, no general relationship exists between the molecular/electronic structures or domain size and the specific catalytic Acidity of the supported tungsten oxide phases present in the model-supported WO3 catalysts.
Howon Lee - One of the best experts on this subject based on the ideXlab platform.
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effect of divalent metal component meii on the catalytic performance of meiife2o4 catalysts in the oxidative dehydrogenation of n butene to 1 3 butadiene
Catalysis Letters, 2008Co-Authors: Howon Lee, Taejin Kim, Ji Chul Jung, Heesoo Kim, Youngmin Chung, Seong Jun Lee, Yong Seung Kim, In Kyu SongAbstract:A series of metal ferrite (MeIIFe2O4) catalysts were prepared by a co-precipitation method with a variation of divalent metal component (MeII = Zn, Mg, Mn, Ni, Co, and Cu) for use in the oxidative dehydrogenation of n-butene to 1,3-butadiene. Successful formation of metal ferrite catalysts with a random spinel structure was confirmed by XRD, ICP-AES, and XPS analyses. The catalytic performance of metal ferrite catalysts in the oxidative dehydrogenation of n-butene strongly depended on the identity of divalent metal component. Acid properties of metal ferrite catalysts were measured by NH3-TPD experiments, with an aim of correlating the catalytic performance with the acid property of the catalysts. It was revealed that the yield for 1,3-butadiene increased with increasing Surface Acidity of the catalyst. Among the catalysts tested, ZnFe2O4 catalyst with the largest Surface Acidity showed the best catalytic performance in the oxidative dehydrogenation of n-butene.
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effect of divalent metal component me ii on the catalytic performance of me ii fe 2 o 4 catalysts in the oxidative dehydrogenation of n butene to 1 3 butadiene
Catalysis Letters, 2008Co-Authors: Howon Lee, Taejin Kim, Ji Chul Jung, Heesoo Kim, Youngmin Chung, Seong Jun Lee, Yong Seung Kim, In Kyu SongAbstract:A series of metal ferrite (MeIIFe2O4) catalysts were prepared by a co-precipitation method with a variation of divalent metal component (MeII = Zn, Mg, Mn, Ni, Co, and Cu) for use in the oxidative dehydrogenation of n-butene to 1,3-butadiene. Successful formation of metal ferrite catalysts with a random spinel structure was confirmed by XRD, ICP-AES, and XPS analyses. The catalytic performance of metal ferrite catalysts in the oxidative dehydrogenation of n-butene strongly depended on the identity of divalent metal component. Acid properties of metal ferrite catalysts were measured by NH3-TPD experiments, with an aim of correlating the catalytic performance with the acid property of the catalysts. It was revealed that the yield for 1,3-butadiene increased with increasing Surface Acidity of the catalyst. Among the catalysts tested, ZnFe2O4 catalyst with the largest Surface Acidity showed the best catalytic performance in the oxidative dehydrogenation of n-butene.
