A post-synthetic modification strategy has been used to prepare three solid base catalysts, including Er(btc)(ED)075(H2O)0.25 (2, btc = 1,3,5-benzenetricarboxylates, ED = 1,2-ethanediamine), Er(btc)(PP)0.5...A post-synthetic modification strategy has been used to prepare three solid base catalysts, including Er(btc)(ED)075(H2O)0.25 (2, btc = 1,3,5-benzenetricarboxylates, ED = 1,2-ethanediamine), Er(btc)(PP)0.55(H20)0.45 (3, PP = piperazine), and Er(btc)(DABCO)0.15(H2O)0.85 (4, DABCO = 1,4- diazabicyclo[2.2.2]octane), by grafting three different diamines onto the coordinatively unsaturated Er(III) ions into the channels of the desolvated lanthanide metal-organic framework (Er(otc)). The resulting metal-organic frameworks were characterized by elemental analysis, thermogravimetric analysis, powder X-ray diffraction, and N2 adsorption. Based on its higher loading ratio of the diamine, as well as its greater stability and porosity, catalyst 2 exhibited higher catalytic activity and reusability than catalysts 3 and 4- for the Knoevenagel condensation reaction. The catalytic mechanism of 2 has also been investigated using size-selective catalysis tests.展开更多
The construction of S‐scheme heterojunction photocatalysts has been regarded as an effective avenue to facilitate the conversion of solar energy to fuel.However,there are still considerable challenges with regard to ...The construction of S‐scheme heterojunction photocatalysts has been regarded as an effective avenue to facilitate the conversion of solar energy to fuel.However,there are still considerable challenges with regard to efficient charge transfer,the abundance of catalytic sites,and extended light absorption.Herein,an S‐scheme heterojunction of 2D/2D zinc porphyrin‐based metal‐organic frameworks/BiVO_(4)nanosheets(Zn‐MOF/BVON)was fabricated for efficient photocatalytic CO_(2)conversion.The optimal one shows a 22‐fold photoactivity enhancement when compared to the previously reported BiVO4 nanoflake(ca.15 nm),and even exhibits~2‐time improvement than the traditional g‐C3N4/BiVO4 heterojunction.The excellent photoactivities are ascribed to the strengthened S‐scheme charge transfer and separation,promoted CO_(2)activation by the well‐dispersed metal nodes Zn_(2)(COO)_(4)in the Zn‐MOF,and extended visible light response range based on the results of the electrochemical reduction,electron paramagnetic resonance,and in‐situ diffuse reflectance infrared Fourier transform spectroscopy.The dimension‐matched Zn‐MOF/BVON S‐scheme heterojunction endowed with highly efficient charge separation and abundant catalytic active sites contributed to the superior CO2 conversion.This study offers a facile strategy for constructing S‐scheme heterojunctions involving porphyrin‐based MOFs for solar fuel production.展开更多
In order to explore the influence of modification sites of functional groups on landfill gas (CO2/CH4) separation performance of metal-organic frameworks (MOFs), six types of or- ganic linkers and three types of f...In order to explore the influence of modification sites of functional groups on landfill gas (CO2/CH4) separation performance of metal-organic frameworks (MOFs), six types of or- ganic linkers and three types of functional groups (i.e. -F, -NH2, -CH3) were used to construct 36 MOFs of pcu topology based on copper paddlewheel. Grand canonical Monte Carlo sim- ulations were performed in this work to evaluate the separation performance of MOFs at low (vacuum swing adsorption) and high (pressure swing adsorption) pressures, respectively. Simulation results demonstrated that CO2 working capacity of the unfunctionalized MOFs generally exhibits pore-size dependence at 1 bar, which increases with the decrease in pore sizes. It was also found that -NH2 funetionalized MOFs exhibit the highest CO2 uptake due to the enhanced Coulombic interactions between the polar -NH2 groups and the quadrupole moment of CO2 molecules, which is followed by -CH3 and -F functionalized ones. Moreover, positioning the functional groups -NH2 and -CH3 at sites far from the metal node (site b) exhibits more significant enhancement on CO2/CH4 separation performance compared to that adjacent to the metal node (site a).展开更多
With increasing knowledge of the molecular mechanisms of endogenous RNA interference,systemic delivery of small interfering RNA(siRNA) via targeted nanoparticles has emerged as a potential strategy for cancer gene t...With increasing knowledge of the molecular mechanisms of endogenous RNA interference,systemic delivery of small interfering RNA(siRNA) via targeted nanoparticles has emerged as a potential strategy for cancer gene therapy.In this study,a novel formulation[liposome-protamine-chondroitin sulfate nanoparticles(LPC-NP)]was developed for siRNA delivery by self-assembling with charge-charge interaction.The LPC-NP was further modified by DSPE-PEG_(2000) and DSPE-PEG_(2000)-T7 by the post-insertion method.T7,a transferrin-like seven-amino acid peptide,is a targeting ligand for transferrin receptor-overexpressed MCF-7 breast cancer cells.The particle size and zeta potential of LPC-NP were approximately 90 nm and +35 mV,respectively. It was shown that PEG modification could significantly decrease aggregation of LPC-NP in serum,and T7 peptide modified LPC-NP could significantly increase the cellular uptake and the gene-silencing effect of siRNA.In vitro cytotoxicity assay exhibited that significant cell growth inhibition was achieved in MCF-7 cells after the delivery of anti-EGFR siRNA.Our encouraging results suggested that T7-modified LPC-NP might be a promising carrier for RNAi-based tumor therapy.展开更多
基金supported by the National Natural Science Foundation of China(21372087)~~
文摘A post-synthetic modification strategy has been used to prepare three solid base catalysts, including Er(btc)(ED)075(H2O)0.25 (2, btc = 1,3,5-benzenetricarboxylates, ED = 1,2-ethanediamine), Er(btc)(PP)0.55(H20)0.45 (3, PP = piperazine), and Er(btc)(DABCO)0.15(H2O)0.85 (4, DABCO = 1,4- diazabicyclo[2.2.2]octane), by grafting three different diamines onto the coordinatively unsaturated Er(III) ions into the channels of the desolvated lanthanide metal-organic framework (Er(otc)). The resulting metal-organic frameworks were characterized by elemental analysis, thermogravimetric analysis, powder X-ray diffraction, and N2 adsorption. Based on its higher loading ratio of the diamine, as well as its greater stability and porosity, catalyst 2 exhibited higher catalytic activity and reusability than catalysts 3 and 4- for the Knoevenagel condensation reaction. The catalytic mechanism of 2 has also been investigated using size-selective catalysis tests.
文摘The construction of S‐scheme heterojunction photocatalysts has been regarded as an effective avenue to facilitate the conversion of solar energy to fuel.However,there are still considerable challenges with regard to efficient charge transfer,the abundance of catalytic sites,and extended light absorption.Herein,an S‐scheme heterojunction of 2D/2D zinc porphyrin‐based metal‐organic frameworks/BiVO_(4)nanosheets(Zn‐MOF/BVON)was fabricated for efficient photocatalytic CO_(2)conversion.The optimal one shows a 22‐fold photoactivity enhancement when compared to the previously reported BiVO4 nanoflake(ca.15 nm),and even exhibits~2‐time improvement than the traditional g‐C3N4/BiVO4 heterojunction.The excellent photoactivities are ascribed to the strengthened S‐scheme charge transfer and separation,promoted CO_(2)activation by the well‐dispersed metal nodes Zn_(2)(COO)_(4)in the Zn‐MOF,and extended visible light response range based on the results of the electrochemical reduction,electron paramagnetic resonance,and in‐situ diffuse reflectance infrared Fourier transform spectroscopy.The dimension‐matched Zn‐MOF/BVON S‐scheme heterojunction endowed with highly efficient charge separation and abundant catalytic active sites contributed to the superior CO2 conversion.This study offers a facile strategy for constructing S‐scheme heterojunctions involving porphyrin‐based MOFs for solar fuel production.
基金supported by the National Natural Science Foundation of China(No.51606081)the Basic Research Foundation of Shenzhen(No.JCYJ20160506170043770)
文摘In order to explore the influence of modification sites of functional groups on landfill gas (CO2/CH4) separation performance of metal-organic frameworks (MOFs), six types of or- ganic linkers and three types of functional groups (i.e. -F, -NH2, -CH3) were used to construct 36 MOFs of pcu topology based on copper paddlewheel. Grand canonical Monte Carlo sim- ulations were performed in this work to evaluate the separation performance of MOFs at low (vacuum swing adsorption) and high (pressure swing adsorption) pressures, respectively. Simulation results demonstrated that CO2 working capacity of the unfunctionalized MOFs generally exhibits pore-size dependence at 1 bar, which increases with the decrease in pore sizes. It was also found that -NH2 funetionalized MOFs exhibit the highest CO2 uptake due to the enhanced Coulombic interactions between the polar -NH2 groups and the quadrupole moment of CO2 molecules, which is followed by -CH3 and -F functionalized ones. Moreover, positioning the functional groups -NH2 and -CH3 at sites far from the metal node (site b) exhibits more significant enhancement on CO2/CH4 separation performance compared to that adjacent to the metal node (site a).
基金National Basic Research Program of China(973 Program,Grant No.2007CB935800 and 2009CB930300)Beijing Natural Science foundation(Grant No.7112089)
文摘With increasing knowledge of the molecular mechanisms of endogenous RNA interference,systemic delivery of small interfering RNA(siRNA) via targeted nanoparticles has emerged as a potential strategy for cancer gene therapy.In this study,a novel formulation[liposome-protamine-chondroitin sulfate nanoparticles(LPC-NP)]was developed for siRNA delivery by self-assembling with charge-charge interaction.The LPC-NP was further modified by DSPE-PEG_(2000) and DSPE-PEG_(2000)-T7 by the post-insertion method.T7,a transferrin-like seven-amino acid peptide,is a targeting ligand for transferrin receptor-overexpressed MCF-7 breast cancer cells.The particle size and zeta potential of LPC-NP were approximately 90 nm and +35 mV,respectively. It was shown that PEG modification could significantly decrease aggregation of LPC-NP in serum,and T7 peptide modified LPC-NP could significantly increase the cellular uptake and the gene-silencing effect of siRNA.In vitro cytotoxicity assay exhibited that significant cell growth inhibition was achieved in MCF-7 cells after the delivery of anti-EGFR siRNA.Our encouraging results suggested that T7-modified LPC-NP might be a promising carrier for RNAi-based tumor therapy.