The intrinsic kinetics of oxidative dehydrogenation of propane with CO2 has been investigated over Cr/MSU-1 catalyst in a fixed bed reactor. Without limitations of both internal and external diffusion, intrinsic kinet...The intrinsic kinetics of oxidative dehydrogenation of propane with CO2 has been investigated over Cr/MSU-1 catalyst in a fixed bed reactor. Without limitations of both internal and external diffusion, intrinsic kinetic data were obtained under the following conditions： 490-530 °C, space velocity of 3600？6000 mL·h-1·g-1 and 3/1 molar ratio for CO2/C3H8 under normal pressure. Based on Langmuir-Hinshelwood mechanism, the kinetic models were established, and they were validated by statistical analysis. The parameters were estimated using Simplex Method combined with Universal Global Optimization Algorithm. The model, taking the surface reaction process as the rate-determining step, is the best one in agreement with the experimental data.展开更多
Propane dehydrogenation(PDH), employing Pt-or Cr-based catalysts, represents an emerging industrial route for propylene production. Due to the scarcity of platinum and the toxicity of chromium, alternative PDH catalys...Propane dehydrogenation(PDH), employing Pt-or Cr-based catalysts, represents an emerging industrial route for propylene production. Due to the scarcity of platinum and the toxicity of chromium, alternative PDH catalysts are being pursued. Herein, we report the construction of Zn-containing zeolite catalysts,namely Zn@S-1, for PDH reaction. Well-isolated zinc cations are successfully trapped and stabilized by the Si-OH groups in S-1 zeolites via in-situ hydrothermal synthesis. The as-prepared Zn@S-1 catalysts exhibit good dehydrogenation activity, high propylene selectivity, and regeneration capability in PDH reaction under employed conditions. The in-situ partial reduction of zinc species is observed and the partially reduced zinc cations are definitely identified as the active sites for PDH reaction.展开更多
Ternary multifunctional A<sub>1</sub>Zn<sub>y</sub>Zr<sub>z</sub>O<sub>n</sub> catalysts are prepared by introducing A-site transition metals with the redox capability i...Ternary multifunctional A<sub>1</sub>Zn<sub>y</sub>Zr<sub>z</sub>O<sub>n</sub> catalysts are prepared by introducing A-site transition metals with the redox capability into binary Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub>. Structure and morphology were investigated by means of XRD, BET and FESEM, respectively. Activity data showed that Cr addition exhibited obvious beneficial effect to promote isobutene production from direct conversion of bio-ethanol compared to other A-site metal dopants. A significant higher yield of isobutene over Cr-promoted Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub> catalyst was also observed with respect to its binary Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub> counterpart. The choice of A-site metal is of prime importance in the isobutene production, catalyzing mainly the ethanol dehydrogenation, meanwhile the appropriate addition of zinc on the catalyst surface is also essential for good isobutene yield.展开更多
The gas-phase dehydrogenation of 1,6-hexanediol(1,6-HDO)toε-caprolactone(ε-CL)over the high-performance Cu-based catalysts is highly desirable,but with grand challenges,because the Cu nanoparticles(NPs)are easy to b...The gas-phase dehydrogenation of 1,6-hexanediol(1,6-HDO)toε-caprolactone(ε-CL)over the high-performance Cu-based catalysts is highly desirable,but with grand challenges,because the Cu nanoparticles(NPs)are easy to be sintered with the low Hüttig temperature(<150℃ vs.>250℃ of reaction temperature).Herein,we report a highly efficient silica-encapsulated nano-Cu catalyst(Cu@SiO_(2)/SiO_(2))prepared via a complexation–impregnation method for the dehydrogenation of 1,6-HDO,exhibiting a 1,6-HDO conversion of 95.3%andε-CL selectivity of 80.0%at 270℃.The catalyst also has the outstanding thermal stability(without sintering up to 270℃ for 100 h on stream),which can be attributed to the effective encapsulation of the SiO_(2)shell.In addition,the reaction network of 1,6-HDO dehydrogenation is proved.Finally,the pyridine-diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and in-situ X-ray photoelectron spectroscopy(XPS)reveal that the Cu^(0) species favor the conversion of 1,6-HDO toε-CL.The synergistic effect of Cu+and Cu^(0) benefits the conversion ofε-CL to 2-methylcyclopentanone(2-MCPN).This study is beneficial for designing the high-performance Cu-based catalysts for 1,6-HDO toε-CL,understanding the reaction network of 1,6-HDO dehydrogenation over the Cu-based catalysts,and offering a strong foundation for the largescale production ofε-CL.展开更多
A novel composite material of TS-1@SBA-16 was synthesized by enwrapping TS-1 zeolite crystals with mesoporous SBA-16 silica. This composite was used as catalyst support for loading Pt-SnOx in the propane dehydr genati...A novel composite material of TS-1@SBA-16 was synthesized by enwrapping TS-1 zeolite crystals with mesoporous SBA-16 silica. This composite was used as catalyst support for loading Pt-SnOx in the propane dehydr genation(PDH) reaction. Catalysts were characterized by means ofN2 adsorption-desorption, XRD, SEM, TEM, XPS, UV-Vis, and Raman spectroscopy. The effect of different contents of TS-1 on PDH was investigated, and the optimal amount of TS-1 was determined to be 10%. The catalyst with TS-1 content of 10% showed the highest PDH activity and the initial conversion of propane over it can achieve 54.5%, higher than those over TS-1 or SB A-16-supported ones. The superior catalytic performance of Pt-SnOx/TS-1 @SBA-16 is related to the synergistic effect of the excellent mass transfer performance through the hierarchical porous structure, suitable acid acidity and electronic effect of Ti species.展开更多
采用水热法制备了Bi_(2)MoO_(6)纳米片催化剂、共沉淀法制备了BiMoV0.15催化剂,在固定床反应器中研究了两种催化剂上丁烯氧化脱氢制丁二烯的本征动力学。采用幂函数模型对不同条件下测得的动力学数据进行了拟合,建立了本征动力学模型,...采用水热法制备了Bi_(2)MoO_(6)纳米片催化剂、共沉淀法制备了BiMoV0.15催化剂,在固定床反应器中研究了两种催化剂上丁烯氧化脱氢制丁二烯的本征动力学。采用幂函数模型对不同条件下测得的动力学数据进行了拟合,建立了本征动力学模型,并得到了活化能和反应级数等相关参数。结果表明:由于不同的反应温度区间拥有不同的速率控制步骤,Bi_(2)MoO_(6)纳米片催化剂和BiMoV_(0.15)催化剂均在653 K左右存在活化能转折现象;且不论在何温度区间,Bi_(2)MoO_(6)纳米片催化剂的活化能均低于BiMoV_(0.15)催化剂的活化能,表明Bi_(2)MoO_(6)纳米片催化剂能有效降低反应能垒,使得反应更易进行;经检验,所得的本征动力学模型可靠性良好。进一步将动力学实验结果与Mars van Krevelen(MvK)机理相结合,阐明了动力学唯象规律和反应机理的内在联系。展开更多
基金supported by the National Natural Science Foundation of China (No. 21006109)the Postdoctoral Science Foundation of China (No. 20080430581)the CASKC Wang Post-Doctoral Fellowship
文摘The intrinsic kinetics of oxidative dehydrogenation of propane with CO2 has been investigated over Cr/MSU-1 catalyst in a fixed bed reactor. Without limitations of both internal and external diffusion, intrinsic kinetic data were obtained under the following conditions： 490-530 °C, space velocity of 3600？6000 mL·h-1·g-1 and 3/1 molar ratio for CO2/C3H8 under normal pressure. Based on Langmuir-Hinshelwood mechanism, the kinetic models were established, and they were validated by statistical analysis. The parameters were estimated using Simplex Method combined with Universal Global Optimization Algorithm. The model, taking the surface reaction process as the rate-determining step, is the best one in agreement with the experimental data.
基金National Natural Science Fund of China(22025203, 21872072)the Municipal Natural Science Fund of Tianjin (18JCJQJC47400) for supporting the work。
文摘Propane dehydrogenation(PDH), employing Pt-or Cr-based catalysts, represents an emerging industrial route for propylene production. Due to the scarcity of platinum and the toxicity of chromium, alternative PDH catalysts are being pursued. Herein, we report the construction of Zn-containing zeolite catalysts,namely Zn@S-1, for PDH reaction. Well-isolated zinc cations are successfully trapped and stabilized by the Si-OH groups in S-1 zeolites via in-situ hydrothermal synthesis. The as-prepared Zn@S-1 catalysts exhibit good dehydrogenation activity, high propylene selectivity, and regeneration capability in PDH reaction under employed conditions. The in-situ partial reduction of zinc species is observed and the partially reduced zinc cations are definitely identified as the active sites for PDH reaction.
文摘Ternary multifunctional A<sub>1</sub>Zn<sub>y</sub>Zr<sub>z</sub>O<sub>n</sub> catalysts are prepared by introducing A-site transition metals with the redox capability into binary Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub>. Structure and morphology were investigated by means of XRD, BET and FESEM, respectively. Activity data showed that Cr addition exhibited obvious beneficial effect to promote isobutene production from direct conversion of bio-ethanol compared to other A-site metal dopants. A significant higher yield of isobutene over Cr-promoted Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub> catalyst was also observed with respect to its binary Zn<sub>1</sub>Zr<sub>8</sub>O<sub>n</sub> counterpart. The choice of A-site metal is of prime importance in the isobutene production, catalyzing mainly the ethanol dehydrogenation, meanwhile the appropriate addition of zinc on the catalyst surface is also essential for good isobutene yield.
基金the National Natural Science Foundation of China(Nos.22179038,22272053,22072043,21773069,and 21703069)the Special Project for Peak Carbon Dioxide Emissions-Carbon Neutrality(No.21DZ1206700)from the Shanghai Municipal ScienceTechnology Commission,and the Key Basic Research Project(No.18JC1412100)from the Shanghai Municipal Science and Technology Commission.
文摘The gas-phase dehydrogenation of 1,6-hexanediol(1,6-HDO)toε-caprolactone(ε-CL)over the high-performance Cu-based catalysts is highly desirable,but with grand challenges,because the Cu nanoparticles(NPs)are easy to be sintered with the low Hüttig temperature(<150℃ vs.>250℃ of reaction temperature).Herein,we report a highly efficient silica-encapsulated nano-Cu catalyst(Cu@SiO_(2)/SiO_(2))prepared via a complexation–impregnation method for the dehydrogenation of 1,6-HDO,exhibiting a 1,6-HDO conversion of 95.3%andε-CL selectivity of 80.0%at 270℃.The catalyst also has the outstanding thermal stability(without sintering up to 270℃ for 100 h on stream),which can be attributed to the effective encapsulation of the SiO_(2)shell.In addition,the reaction network of 1,6-HDO dehydrogenation is proved.Finally,the pyridine-diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and in-situ X-ray photoelectron spectroscopy(XPS)reveal that the Cu^(0) species favor the conversion of 1,6-HDO toε-CL.The synergistic effect of Cu+and Cu^(0) benefits the conversion ofε-CL to 2-methylcyclopentanone(2-MCPN).This study is beneficial for designing the high-performance Cu-based catalysts for 1,6-HDO toε-CL,understanding the reaction network of 1,6-HDO dehydrogenation over the Cu-based catalysts,and offering a strong foundation for the largescale production ofε-CL.
基金Supported by the National Natural Science Foundation of China(Nos.21845201,21761162016,21603148).
文摘A novel composite material of TS-1@SBA-16 was synthesized by enwrapping TS-1 zeolite crystals with mesoporous SBA-16 silica. This composite was used as catalyst support for loading Pt-SnOx in the propane dehydr genation(PDH) reaction. Catalysts were characterized by means ofN2 adsorption-desorption, XRD, SEM, TEM, XPS, UV-Vis, and Raman spectroscopy. The effect of different contents of TS-1 on PDH was investigated, and the optimal amount of TS-1 was determined to be 10%. The catalyst with TS-1 content of 10% showed the highest PDH activity and the initial conversion of propane over it can achieve 54.5%, higher than those over TS-1 or SB A-16-supported ones. The superior catalytic performance of Pt-SnOx/TS-1 @SBA-16 is related to the synergistic effect of the excellent mass transfer performance through the hierarchical porous structure, suitable acid acidity and electronic effect of Ti species.
文摘采用水热法制备了Bi_(2)MoO_(6)纳米片催化剂、共沉淀法制备了BiMoV0.15催化剂,在固定床反应器中研究了两种催化剂上丁烯氧化脱氢制丁二烯的本征动力学。采用幂函数模型对不同条件下测得的动力学数据进行了拟合,建立了本征动力学模型,并得到了活化能和反应级数等相关参数。结果表明:由于不同的反应温度区间拥有不同的速率控制步骤,Bi_(2)MoO_(6)纳米片催化剂和BiMoV_(0.15)催化剂均在653 K左右存在活化能转折现象;且不论在何温度区间,Bi_(2)MoO_(6)纳米片催化剂的活化能均低于BiMoV_(0.15)催化剂的活化能,表明Bi_(2)MoO_(6)纳米片催化剂能有效降低反应能垒,使得反应更易进行;经检验,所得的本征动力学模型可靠性良好。进一步将动力学实验结果与Mars van Krevelen(MvK)机理相结合,阐明了动力学唯象规律和反应机理的内在联系。
