Supported loaded semiconductors (MoO3,ZnO)-TiO2/SiO2 were pre pared by an isovolumetric impregnation method from TiO2/SiO2 pre pared by chemical modification reaction. The chemisorption property and photon a bsorpti...Supported loaded semiconductors (MoO3,ZnO)-TiO2/SiO2 were pre pared by an isovolumetric impregnation method from TiO2/SiO2 pre pared by chemical modification reaction. The chemisorption property and photon a bsorption ability of MoO3-TiO2/SiO2 and ZnO-TiO2/SiO 2 were investigated by BET, UV-Vis DRS, IR and TPD-MS techniques. The gas -phase photocatalytic reaction of CH4 with H2O was performed at 150 ℃ in a fixed-bed annular reactor. The results show that the conversion of met hane and the selectivity of methanol reach to 5.1% and 87.3% respectively over MoO3-TiO2/SiO2, and MoO3-TiO2/SiO2 ex hibits higher photocatalytic acivity than ZnO-TiO2/SiO2.展开更多
Biodiesel was synthesized from soybean oil by transesterification over Li_2SiO_3 catalyst.The Li_2SiO_3 can be used for biodiesel production directly without further drying or thermal pretreatment,no obvious differenc...Biodiesel was synthesized from soybean oil by transesterification over Li_2SiO_3 catalyst.The Li_2SiO_3 can be used for biodiesel production directly without further drying or thermal pretreatment,no obvious difference in the FAME conversion(92.4-96.7%) between the air-exposed catalyst(24-72 h) and the fresh one(94.2%).This leads to important benefits when considering industrial applications of Li_2SiO_3 as a solid catalyst for storing and handling catalyst without taking special actions.展开更多
The deactivation of Ni/SiO2-Al2 O3 catalyst in hydrogenation of crude 1,4-butanediol was investigated.During the operation time of 2140 h,the catalyst showed slow activity decay.Characterization results,for four spent...The deactivation of Ni/SiO2-Al2 O3 catalyst in hydrogenation of crude 1,4-butanediol was investigated.During the operation time of 2140 h,the catalyst showed slow activity decay.Characterization results,for four spent catalysts used at different time,indicated that the main reason of the catalyst deactivation was the deposition of carbonaceous species that covered the active Ni and blocked mesopores of the catalyst.The TPO and SEM measurements revealed that the carbonaceous species included both oligomeric and polymeric species with high C/H ratio and showed sheet.Such carbonaceous species might be eliminated through either direct H2 reduction or the combined oxidation-reduction methodologies.展开更多
8wt%WO3/SiO2 metathesis (disproportionation) catalysts with different pore structures were prepared by the incipient-wetness-impregnation method. The as-synthesized catalysts were characterized by N2 adsorpfion-deso...8wt%WO3/SiO2 metathesis (disproportionation) catalysts with different pore structures were prepared by the incipient-wetness-impregnation method. The as-synthesized catalysts were characterized by N2 adsorpfion-desorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (DRS) and scanning transmission electron microscopy-high-angle annular dark field (STEM HAADF). The results of STEM HAADF showed that WO3 species were not uniformly distributed on the SiO2 support. The experimental results of 8wt%WO3/SiO2 performance in ethene/decene metathesis revealed that the catalytic effect of 8wt%WO3/SiO2 catalyst and coke formation over it were closely related to the support pore structure: The 8wt%WO3/SiO2 catalyst with a more complicated pore structure showed better catalytic performance but the coke deposition rate was also faster.展开更多
The various surface species[H_XRu_3(CO)_9(CCO)]2-X(X=0-2)prepared from impregnation of[PPN]_2[Ru_3(CO)_9(CCO)]on SiO_2-Al_2O_3,SiO_2 and MgO show quite different activities and selectivities for oxygenates and etha...The various surface species[H_XRu_3(CO)_9(CCO)]2-X(X=0-2)prepared from impregnation of[PPN]_2[Ru_3(CO)_9(CCO)]on SiO_2-Al_2O_3,SiO_2 and MgO show quite different activities and selectivities for oxygenates and ethane in ethylene hydroformylation.展开更多
The surface plasmonic resonance(SPR)effect of Bi can effectively improve the light absorption abilities and photogenerated charge carrier separation rate.In this study,a novel ternary heterojunction of g-C3N4/Bi2MoO6/...The surface plasmonic resonance(SPR)effect of Bi can effectively improve the light absorption abilities and photogenerated charge carrier separation rate.In this study,a novel ternary heterojunction of g-C3N4/Bi2MoO6/Bi(CN/BMO/Bi)hollow microsphere was successfully fabricated through solvothermal and in situ reduction methods.The results revealed that the optimal ternary 0.4 CN/BMO/9 Bi photocatalyst exhibited the highest photocatalytic efficiency toward rhodamine B(RhB)degradation with nine times that of pure BMO.The DRS and valence band of the X-ray photoelectron spectroscopy spectrum demonstrate that the band structure of 0.4 CN/BMO/9 Bi is a z-scheme structure.Quenching experiments also provided solid evidence that the·O^2-(at-0.33 eV)is the main species during dye degradation,and the conduction band of g-C3N4 is only the reaction site,demonstrating that the transfer of photogenerated charge carriers of g-C3N4/Bi2 MoO 6/Bi is through an indirect z-scheme structure.Thus,the enhanced photocatalytic performance was mainly ascribed to the synergetic effect of heterojunction structures between g-C3N4 and Bi2MoO6 and the SPR effect of Bi doping,resulting in better optical absorption ability and a lower combination rate of photogenerated charge carriers.The findings in this work provide insight into the synergism of heterostructures and the SPR absorption ability in wastewater treatment.展开更多
摘要Supported loaded semiconductors (MoO3,ZnO)-TiO2/SiO2 were pre pared by an isovolumetric impregnation method from TiO2/SiO2 pre pared by chemical modification reaction. The chemisorption property and photon a bsorption ability of MoO3-TiO2/SiO2 and ZnO-TiO2/SiO 2 were investigated by BET, UV-Vis DRS, IR and TPD-MS techniques. The gas -phase photocatalytic reaction of CH4 with H2O was performed at 150 ℃ in a fixed-bed annular reactor. The results show that the conversion of met hane and the selectivity of methanol reach to 5.1% and 87.3% respectively over MoO3-TiO2/SiO2, and MoO3-TiO2/SiO2 ex hibits higher photocatalytic acivity than ZnO-TiO2/SiO2.
摘要Biodiesel was synthesized from soybean oil by transesterification over Li_2SiO_3 catalyst.The Li_2SiO_3 can be used for biodiesel production directly without further drying or thermal pretreatment,no obvious difference in the FAME conversion(92.4-96.7%) between the air-exposed catalyst(24-72 h) and the fresh one(94.2%).This leads to important benefits when considering industrial applications of Li_2SiO_3 as a solid catalyst for storing and handling catalyst without taking special actions.
基金Supported by the National Natural Science Foundation of China(21673132).
摘要The deactivation of Ni/SiO2-Al2 O3 catalyst in hydrogenation of crude 1,4-butanediol was investigated.During the operation time of 2140 h,the catalyst showed slow activity decay.Characterization results,for four spent catalysts used at different time,indicated that the main reason of the catalyst deactivation was the deposition of carbonaceous species that covered the active Ni and blocked mesopores of the catalyst.The TPO and SEM measurements revealed that the carbonaceous species included both oligomeric and polymeric species with high C/H ratio and showed sheet.Such carbonaceous species might be eliminated through either direct H2 reduction or the combined oxidation-reduction methodologies.
摘要8wt%WO3/SiO2 metathesis (disproportionation) catalysts with different pore structures were prepared by the incipient-wetness-impregnation method. The as-synthesized catalysts were characterized by N2 adsorpfion-desorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (DRS) and scanning transmission electron microscopy-high-angle annular dark field (STEM HAADF). The results of STEM HAADF showed that WO3 species were not uniformly distributed on the SiO2 support. The experimental results of 8wt%WO3/SiO2 performance in ethene/decene metathesis revealed that the catalytic effect of 8wt%WO3/SiO2 catalyst and coke formation over it were closely related to the support pore structure: The 8wt%WO3/SiO2 catalyst with a more complicated pore structure showed better catalytic performance but the coke deposition rate was also faster.
摘要The various surface species[H_XRu_3(CO)_9(CCO)]2-X(X=0-2)prepared from impregnation of[PPN]_2[Ru_3(CO)_9(CCO)]on SiO_2-Al_2O_3,SiO_2 and MgO show quite different activities and selectivities for oxygenates and ethane in ethylene hydroformylation.
基金financially supported by the Science Foundation of China University of Petroleum,Beijing(2462017YJRC048,2462018BJC005)the National Natural Science Foundation of China(51802351)~~
摘要The surface plasmonic resonance(SPR)effect of Bi can effectively improve the light absorption abilities and photogenerated charge carrier separation rate.In this study,a novel ternary heterojunction of g-C3N4/Bi2MoO6/Bi(CN/BMO/Bi)hollow microsphere was successfully fabricated through solvothermal and in situ reduction methods.The results revealed that the optimal ternary 0.4 CN/BMO/9 Bi photocatalyst exhibited the highest photocatalytic efficiency toward rhodamine B(RhB)degradation with nine times that of pure BMO.The DRS and valence band of the X-ray photoelectron spectroscopy spectrum demonstrate that the band structure of 0.4 CN/BMO/9 Bi is a z-scheme structure.Quenching experiments also provided solid evidence that the·O^2-(at-0.33 eV)is the main species during dye degradation,and the conduction band of g-C3N4 is only the reaction site,demonstrating that the transfer of photogenerated charge carriers of g-C3N4/Bi2 MoO 6/Bi is through an indirect z-scheme structure.Thus,the enhanced photocatalytic performance was mainly ascribed to the synergetic effect of heterojunction structures between g-C3N4 and Bi2MoO6 and the SPR effect of Bi doping,resulting in better optical absorption ability and a lower combination rate of photogenerated charge carriers.The findings in this work provide insight into the synergism of heterostructures and the SPR absorption ability in wastewater treatment.