Titanium-containing mesoporous molecular sieves are of great significance in selective catalytic oxidation processes with bulky molecules. Recent researches and developments on the designing and synthesis of Ti-contai...Titanium-containing mesoporous molecular sieves are of great significance in selective catalytic oxidation processes with bulky molecules. Recent researches and developments on the designing and synthesis of Ti-containing mesoporous materials have been reviewed. Various strategies for the preparation of Ti-containing mesoporous materials, such as direct synthesis and post-synthesis, are described. Modifications of Ti-containing mesoporous materials by surface-grafting and atom-planting are also discussed. All approaches aimed mainly at the improving of the stability, the hydrophobicity, and mostly the catalytic activity. Structural and mechanistic features of various synthetic systems are discussed. Ticontaining mesoporous materials in liquid phase catalytic oxidation of organic compounds with H2O2 as an oxidant is briefly summarized, showing their broad utilities for green synthesis of fine chemicals by catalytic oxidative reactions.展开更多
The objective of this work is to study the influences of silica supports and PEG additive on the sorption performance of molecular basket sorbent（MBS） for COcapture consisting of polyethylenimine and one of the foll...The objective of this work is to study the influences of silica supports and PEG additive on the sorption performance of molecular basket sorbent（MBS） for COcapture consisting of polyethylenimine and one of the following supports: SBA-15（2-D structure）, TUD-1（3-D sponge-like structure） and fumed silica HS-5（3-D disordered structure）. Effects of the supports regarding pore structures and pore properties, the PEI loading amount as well as the sorption temperature were examined. Furthermore, polyethylene glycol（PEG） was introduced as an additive into the sorbents and its effect was investigated at different PEI loadings and sorption temperatures. The results suggest that the pore properties of MBS（after PEI loading） play a more important role in the COsorption capacity, rather than those of the supports alone.MBS with 3D pore structure exhibits higher COsorption capacity and amine efficiency than those with 2D-structured support. Among the sorbents studied, fumed silica（HS-5） based MBS showed the highest COsorption capacity in the temperature range of 30-95 °C, probably due to its unique interstitial pores formed by the aggregation of polymer-loaded SiOparticles. It was found that the temperature dependence is directly related to the PEI surface coverage layers. The more PEI surface coverage layers, the higher diffusion barrier for COand the stronger temperature dependence of COcapacity. 3D MBS exceeds 2D MBS at the same PEI coverage layers due to lower diffusion barrier. Adding PEG can significantly enhance the COsorption capacity and improve amine efficiency of all MBS, most likely by alleviating the diffusion barrier within PEI bulk layers through the inter-molecular interaction between PEI and PEG.展开更多
A\} new highly ordered mesostructured silica(possible space group \%Fm3m\%) was synthesized by \{using\} tri\|headgroup quaternary ammonium surfactant \{CH\-3(CH\-2)\-\{17\}N\++(CH\-3)\-2CH\-2CH\-2N\++(CH\-3)\-2CH\-2C...A\} new highly ordered mesostructured silica(possible space group \%Fm3m\%) was synthesized by \{using\} tri\|headgroup quaternary ammonium surfactant \{CH\-3(CH\-2)\-\{17\}N\++(CH\-3)\-2CH\-2CH\-2N\++(CH\-3)\-2CH\-2CH\-2\}CH\-2N\++(CH\-3)\-3\53Br\+-(C\-\{18\|2\|3\|1\}) under a basic condition. The cubic mesoporous silica product has an \{average\} pore size of 2.9 nm, a large BET specific surface area of 991 m\+2/g and a large pore volume of \{0.98 cm\+3/g\}.展开更多
Highly ordered hexagonal mesoporous silica SBA-15 with tunable morphology such as donut-like has been synthesized through the cosolvent approach. Donut-like SBA-15 prepared by using DMF cosolvent shows highly ordered ...Highly ordered hexagonal mesoporous silica SBA-15 with tunable morphology such as donut-like has been synthesized through the cosolvent approach. Donut-like SBA-15 prepared by using DMF cosolvent shows highly ordered circle channels and large mesopore size of 9.9 nm and pore volume of 1.45 cm3/g. Cosurfactant approach has also been used to control the morphology of SBA-15, resulting that highly ordered hard spheres (uniformed diameter—800 nm) mesoporous silica are formed. The morphology of mesoporous SBA-15 is much depended on the surface curvature energy of interface of inorganic silica and organic block copolymer species.展开更多
基金the national natural science foundation of China (No.20541002)SINOPEC basic research foundation (X504034) Zhejiang provincial natural science foundation (No.Y405064)
文摘Titanium-containing mesoporous molecular sieves are of great significance in selective catalytic oxidation processes with bulky molecules. Recent researches and developments on the designing and synthesis of Ti-containing mesoporous materials have been reviewed. Various strategies for the preparation of Ti-containing mesoporous materials, such as direct synthesis and post-synthesis, are described. Modifications of Ti-containing mesoporous materials by surface-grafting and atom-planting are also discussed. All approaches aimed mainly at the improving of the stability, the hydrophobicity, and mostly the catalytic activity. Structural and mechanistic features of various synthetic systems are discussed. Ticontaining mesoporous materials in liquid phase catalytic oxidation of organic compounds with H2O2 as an oxidant is briefly summarized, showing their broad utilities for green synthesis of fine chemicals by catalytic oxidative reactions.
基金the support of this work at Penn State by the U.S.Department of Energy,National Energy Technology Laboratorythe financial support by the China Scholarship Council,the Natural Science Foundation of China(No.51176034)the Open Fund of Key Laboratory of Coal-Based CO2 Capture and Geological Storage of Jiangsu Province(2016A05)
文摘The objective of this work is to study the influences of silica supports and PEG additive on the sorption performance of molecular basket sorbent（MBS） for COcapture consisting of polyethylenimine and one of the following supports: SBA-15（2-D structure）, TUD-1（3-D sponge-like structure） and fumed silica HS-5（3-D disordered structure）. Effects of the supports regarding pore structures and pore properties, the PEI loading amount as well as the sorption temperature were examined. Furthermore, polyethylene glycol（PEG） was introduced as an additive into the sorbents and its effect was investigated at different PEI loadings and sorption temperatures. The results suggest that the pore properties of MBS（after PEI loading） play a more important role in the COsorption capacity, rather than those of the supports alone.MBS with 3D pore structure exhibits higher COsorption capacity and amine efficiency than those with 2D-structured support. Among the sorbents studied, fumed silica（HS-5） based MBS showed the highest COsorption capacity in the temperature range of 30-95 °C, probably due to its unique interstitial pores formed by the aggregation of polymer-loaded SiOparticles. It was found that the temperature dependence is directly related to the PEI surface coverage layers. The more PEI surface coverage layers, the higher diffusion barrier for COand the stronger temperature dependence of COcapacity. 3D MBS exceeds 2D MBS at the same PEI coverage layers due to lower diffusion barrier. Adding PEG can significantly enhance the COsorption capacity and improve amine efficiency of all MBS, most likely by alleviating the diffusion barrier within PEI bulk layers through the inter-molecular interaction between PEI and PEG.
文摘A\} new highly ordered mesostructured silica(possible space group \%Fm3m\%) was synthesized by \{using\} tri\|headgroup quaternary ammonium surfactant \{CH\-3(CH\-2)\-\{17\}N\++(CH\-3)\-2CH\-2CH\-2N\++(CH\-3)\-2CH\-2CH\-2\}CH\-2N\++(CH\-3)\-3\53Br\+-(C\-\{18\|2\|3\|1\}) under a basic condition. The cubic mesoporous silica product has an \{average\} pore size of 2.9 nm, a large BET specific surface area of 991 m\+2/g and a large pore volume of \{0.98 cm\+3/g\}.
文摘Highly ordered hexagonal mesoporous silica SBA-15 with tunable morphology such as donut-like has been synthesized through the cosolvent approach. Donut-like SBA-15 prepared by using DMF cosolvent shows highly ordered circle channels and large mesopore size of 9.9 nm and pore volume of 1.45 cm3/g. Cosurfactant approach has also been used to control the morphology of SBA-15, resulting that highly ordered hard spheres (uniformed diameter—800 nm) mesoporous silica are formed. The morphology of mesoporous SBA-15 is much depended on the surface curvature energy of interface of inorganic silica and organic block copolymer species.
