Mesostructured Co3O4-CeO2 composite was found to be an effective catalytic material for the complete oxidation of benzene. The Co3O4-CeO2 catalysts with different Co/Ce ratios （mol/mol） were prepared via the nanocas...Mesostructured Co3O4-CeO2 composite was found to be an effective catalytic material for the complete oxidation of benzene. The Co3O4-CeO2 catalysts with different Co/Ce ratios （mol/mol） were prepared via the nanocasting method and the mesostructure was replicated from two-dimensional （2D） hexagonal SBA-15 and three-dimensional （3D） cubic KIT-6 silicas, respectively. All the obtained Co3O4-CeO2 catalysts exhibited the similar symmetry with the parent silicas and well ordered mesostructures. The Co3O4- CeO2 catalysts with 2D mesostructure showed lower catalytic activities than the corresponding 3D materials. The Co3O4-CeO2 catalyst nanocasted from KIT-6 and with the Co/Ce ratio of 16/1 possessed the best catalytic benzene oxidation activity due to larger quantities of surface hydroxyl groups and surface oxygenated species. The mesostructured Co3O4-CeO2 material thus shows great potential as a promising eco-environmental catalyst for benzene effective elimination.展开更多
Propylene,a readily accessible and economically viable light olefin,has garnered substantial interest for its potential conversion into valuable higher olefins through oligomerization processes.The distribution of pro...Propylene,a readily accessible and economically viable light olefin,has garnered substantial interest for its potential conversion into valuable higher olefins through oligomerization processes.The distribution of products is profoundly influenced by the catalyst structure.In this study,Fe_(2)O_(3)-doped NiSO_(4)/Al_(2)O_(3) catalysts have been meticulously developed to facilitate the selective trimerization of propylene under mild conditions.Significantly,the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst demonstrates an enhanced reaction rate(48.5 mmol_(C3)/(g_(cat).·h)),alongside a high yield of C9(~32.2%),significantly surpassing the performance of the NiSO_(4)/Al_(2)O_(3) catalyst(C9:~24.1%).The incorporation of Fe_(2)O_(3) modifies the migration process of sulfate ions,altering the Lewis acidity of the electron-deficient Ni and Fe sites on the catalyst and resulting a shift in product distribution from a Schulz-Flory distribution to a Poisson distribution.This shift is primarily ascribed to the heightened energy barrier for theβ-H elimination reaction in the C6 alkyl intermediates on the doped catalyst,further promoting polymerization to yield a greater quantity of Type II C9.Furthermore,the validation of the Cossee-Arlman mechanism within the reaction pathway has been confirmed.It is noteworthy that the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst exhibits remarkable stability exceeding 80 h in the selective trimerization of propylene.These research findings significantly enhance our understanding of the mechanisms underlying olefin oligomerization reactions and provide invaluable insights for the development of more effective catalysts.展开更多
CeO2-Co3O4 catalysts for low-temperature CO oxidation were prepared by a co-precipitation method. In combination with the characterization methods of N2 adsorption/desorption, XRD, temperature-programmed reduction （...CeO2-Co3O4 catalysts for low-temperature CO oxidation were prepared by a co-precipitation method. In combination with the characterization methods of N2 adsorption/desorption, XRD, temperature-programmed reduction （TPR）, and FT-IR, the influence of the cerium content on the catalytic performance of CeO2-Co3O4 was investigated. The results indicate that the prepared CeO2-Co3O4 catalysts exhibit a better activity than that of pure CeO2 or pure Co3O4. The catalyst with the Ce/Co atomic ratio 1 ： 16 exhibits the best activity, which converts 77% of CO at room temperature and completely oxidizes CO at 45 ℃.展开更多
2,5-dimethyfuran(DMF), which is produced from 5-hydroxymethyfurfural(HMF) by hydrodeoxygenation(HDO), is a high quality fuel due to the high heating value, the high octane number and the suitable boiling point. Select...2,5-dimethyfuran(DMF), which is produced from 5-hydroxymethyfurfural(HMF) by hydrodeoxygenation(HDO), is a high quality fuel due to the high heating value, the high octane number and the suitable boiling point. Selective hydrogenation of HMF into liquid fuel DMF has been widely researched. In this paper, Co_3O_4 catalyst was prepared by co-precipitation and was reduced at different temperatures to form Co–CoO_x catalysts. The characterization of catalysts was tested by XRD, TEM, XPS, TPR, BET and NH3-TPD.Co–CoO_x possessed a high amount of Co metal and CoO_x acidic sites, wherein Co worked as the active hydrogenation sites and CoO_x acted as the acid promoter to facilitate the selective HDO of HMF to DMF.The synergistic effect of Co–CoO_x is the key for HDO of HMF, obtaining 83.3% of DMF yield at 170 °C, 12 h and the reduction temperature of 400 °C. This method not only saves the catalyst cost, but also promotes the utilization of biomass energy.展开更多
Solubilities and properties (density, conductivity and pH value) of solutions in the quaternary system Li +,K +//CO 2- 3,B 4O 2- 7-H 2O at 288 K were experimentally studied with the isothermal equilibrium method. The ...Solubilities and properties (density, conductivity and pH value) of solutions in the quaternary system Li +,K +//CO 2- 3,B 4O 2- 7-H 2O at 288 K were experimentally studied with the isothermal equilibrium method. The phase diagram of the system consisted of two invariant points E and F, five univariant curves, and four crystallization fields that belonged to K 2CO 3·3/2H 2O,Li 2 B 4O 7·3H 2O, K 2 B 4O 7 ·4H 2O and Li 2CO 3. The composition of the solution corresponding to E was w(CO 2- 3)=2.27 %, w(B 4O 2- 7) =6.05 %, w(K + ) =4.30%,w(Li + )=0.30 % and the equilibrium solids were Li 2 B 4O 7· 3H 2O+K 2 B 4O 7·4H 2O+Li 2CO 3;The composition of the solution for F was w(CO 2- 3) =22.45%,w(B 4O 2- 7)=1.88%,w(K + )=29.96%,w(Li + )=0.03% and the equilibrium solids were K 2CO 3·3/2H 2O+ K 2 B 4O 7·4H 2O+Li 2CO 3. K 2CO 3 possesses strong salting-out effect on K 2 B 4O 7,Li 2CO 3 and Li 2 B 4O 7.展开更多
Compound [Co 3(BTC)(HBTC)(H 2BTC)(C 2H 4O 2) 3]·3(DMF)·6(H 3O) was synthesized under mild conditions and its crystal structure was determined by using single crystal X-ray diffraction. The crystal structure ...Compound [Co 3(BTC)(HBTC)(H 2BTC)(C 2H 4O 2) 3]·3(DMF)·6(H 3O) was synthesized under mild conditions and its crystal structure was determined by using single crystal X-ray diffraction. The crystal structure was solved by direct method and refined by full-matrix least-square method. The crystal is monoclinic and belongs to space group Cc with a=2.645 3(5) nm, b= 1.670 4(3) nm, c=1\^821 6(4) nm, β=128.16(3) °, V=6.329(2) nm 3, Z=2 , D c=20.200 Mg/m 3, M r= 1 314.744, μ=10.274 mm -1, F(000) =38 226, GOF=0.99, R=0.094 1, ωR=0.257 3.展开更多
基金supported by the National Natural Science Funds for Distinguished Young Scholar (No.20725723)the National Basic Research Program of China(No. 2010CB732300)the National High Technology Research and Development Program of China (No.2006AA06A310)
文摘Mesostructured Co3O4-CeO2 composite was found to be an effective catalytic material for the complete oxidation of benzene. The Co3O4-CeO2 catalysts with different Co/Ce ratios （mol/mol） were prepared via the nanocasting method and the mesostructure was replicated from two-dimensional （2D） hexagonal SBA-15 and three-dimensional （3D） cubic KIT-6 silicas, respectively. All the obtained Co3O4-CeO2 catalysts exhibited the similar symmetry with the parent silicas and well ordered mesostructures. The Co3O4- CeO2 catalysts with 2D mesostructure showed lower catalytic activities than the corresponding 3D materials. The Co3O4-CeO2 catalyst nanocasted from KIT-6 and with the Co/Ce ratio of 16/1 possessed the best catalytic benzene oxidation activity due to larger quantities of surface hydroxyl groups and surface oxygenated species. The mesostructured Co3O4-CeO2 material thus shows great potential as a promising eco-environmental catalyst for benzene effective elimination.
文摘Propylene,a readily accessible and economically viable light olefin,has garnered substantial interest for its potential conversion into valuable higher olefins through oligomerization processes.The distribution of products is profoundly influenced by the catalyst structure.In this study,Fe_(2)O_(3)-doped NiSO_(4)/Al_(2)O_(3) catalysts have been meticulously developed to facilitate the selective trimerization of propylene under mild conditions.Significantly,the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst demonstrates an enhanced reaction rate(48.5 mmol_(C3)/(g_(cat).·h)),alongside a high yield of C9(~32.2%),significantly surpassing the performance of the NiSO_(4)/Al_(2)O_(3) catalyst(C9:~24.1%).The incorporation of Fe_(2)O_(3) modifies the migration process of sulfate ions,altering the Lewis acidity of the electron-deficient Ni and Fe sites on the catalyst and resulting a shift in product distribution from a Schulz-Flory distribution to a Poisson distribution.This shift is primarily ascribed to the heightened energy barrier for theβ-H elimination reaction in the C6 alkyl intermediates on the doped catalyst,further promoting polymerization to yield a greater quantity of Type II C9.Furthermore,the validation of the Cossee-Arlman mechanism within the reaction pathway has been confirmed.It is noteworthy that the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst exhibits remarkable stability exceeding 80 h in the selective trimerization of propylene.These research findings significantly enhance our understanding of the mechanisms underlying olefin oligomerization reactions and provide invaluable insights for the development of more effective catalysts.
文摘CeO2-Co3O4 catalysts for low-temperature CO oxidation were prepared by a co-precipitation method. In combination with the characterization methods of N2 adsorption/desorption, XRD, temperature-programmed reduction （TPR）, and FT-IR, the influence of the cerium content on the catalytic performance of CeO2-Co3O4 was investigated. The results indicate that the prepared CeO2-Co3O4 catalysts exhibit a better activity than that of pure CeO2 or pure Co3O4. The catalyst with the Ce/Co atomic ratio 1 ： 16 exhibits the best activity, which converts 77% of CO at room temperature and completely oxidizes CO at 45 ℃.
基金financially supported by the National Natural Science Foundation of China(51576199 and 51536009)the Natural Science Fund of Guangdong Province(2017A030308010)
文摘2,5-dimethyfuran(DMF), which is produced from 5-hydroxymethyfurfural(HMF) by hydrodeoxygenation(HDO), is a high quality fuel due to the high heating value, the high octane number and the suitable boiling point. Selective hydrogenation of HMF into liquid fuel DMF has been widely researched. In this paper, Co_3O_4 catalyst was prepared by co-precipitation and was reduced at different temperatures to form Co–CoO_x catalysts. The characterization of catalysts was tested by XRD, TEM, XPS, TPR, BET and NH3-TPD.Co–CoO_x possessed a high amount of Co metal and CoO_x acidic sites, wherein Co worked as the active hydrogenation sites and CoO_x acted as the acid promoter to facilitate the selective HDO of HMF to DMF.The synergistic effect of Co–CoO_x is the key for HDO of HMF, obtaining 83.3% of DMF yield at 170 °C, 12 h and the reduction temperature of 400 °C. This method not only saves the catalyst cost, but also promotes the utilization of biomass energy.
文摘Solubilities and properties (density, conductivity and pH value) of solutions in the quaternary system Li +,K +//CO 2- 3,B 4O 2- 7-H 2O at 288 K were experimentally studied with the isothermal equilibrium method. The phase diagram of the system consisted of two invariant points E and F, five univariant curves, and four crystallization fields that belonged to K 2CO 3·3/2H 2O,Li 2 B 4O 7·3H 2O, K 2 B 4O 7 ·4H 2O and Li 2CO 3. The composition of the solution corresponding to E was w(CO 2- 3)=2.27 %, w(B 4O 2- 7) =6.05 %, w(K + ) =4.30%,w(Li + )=0.30 % and the equilibrium solids were Li 2 B 4O 7· 3H 2O+K 2 B 4O 7·4H 2O+Li 2CO 3;The composition of the solution for F was w(CO 2- 3) =22.45%,w(B 4O 2- 7)=1.88%,w(K + )=29.96%,w(Li + )=0.03% and the equilibrium solids were K 2CO 3·3/2H 2O+ K 2 B 4O 7·4H 2O+Li 2CO 3. K 2CO 3 possesses strong salting-out effect on K 2 B 4O 7,Li 2CO 3 and Li 2 B 4O 7.
基金Research Project from Department of Science and Technology of Shandong Province(2012GGA01012)Scientific ResearchFoundation for the Returned Overseas Chinese Scholars of State Education Ministry(2004-527)
文摘Compound [Co 3(BTC)(HBTC)(H 2BTC)(C 2H 4O 2) 3]·3(DMF)·6(H 3O) was synthesized under mild conditions and its crystal structure was determined by using single crystal X-ray diffraction. The crystal structure was solved by direct method and refined by full-matrix least-square method. The crystal is monoclinic and belongs to space group Cc with a=2.645 3(5) nm, b= 1.670 4(3) nm, c=1\^821 6(4) nm, β=128.16(3) °, V=6.329(2) nm 3, Z=2 , D c=20.200 Mg/m 3, M r= 1 314.744, μ=10.274 mm -1, F(000) =38 226, GOF=0.99, R=0.094 1, ωR=0.257 3.
