Constructed by selecting appropriate building blocks,covalent organic frameworks(COFs)can be endowed with a variety of specific functions.Herein,we successfully synthesized an imine‐linked H_(2)PReBpy‐COF with the C...Constructed by selecting appropriate building blocks,covalent organic frameworks(COFs)can be endowed with a variety of specific functions.Herein,we successfully synthesized an imine‐linked H_(2)PReBpy‐COF with the CO_(2) reduction catalyst[ReI(bpy)(CO)_(3)Cl]and the porphyrin photosensitizer as the monomeric building units.The light‐harvesting properties of the porphyrin itself,augmented by the extendedπ‐conjugated planar structure of 2D COF,enable H_(2)PReBpy‐COF the excellent light‐harvesting capability,efficient charge separation,and fast interfacial charge transfer.In addition,a large amount of uniformly distributed[ReI(bpy)(CO)_(3)Cl]units offer H_(2)PReBpy‐COF an excellent activity toward photocatalytic CO_(2) reduction with moderate selectivity and reusability.This study demonstrated a proof of concept in which the advantages of COFs and functional monomers are rationally integrated for photocatalytic solar fuel conversion.展开更多
In this study, cucurbit[8]uril （CB[8]） was utilized as a kind of new adsorbent to remove Pb^2＋ ions from aqueous solution. With the solution pH increased from 2 to 6, the removal efficiency of adsorption increased ...In this study, cucurbit[8]uril （CB[8]） was utilized as a kind of new adsorbent to remove Pb^2＋ ions from aqueous solution. With the solution pH increased from 2 to 6, the removal efficiency of adsorption increased from 55.6% to 74.5%correspondingly. The uptake of Pb^2＋ increased rapidly in the initial 30 min, and then the adsorption rate became slower. The Pseudo-second order model could be used to interpret the adsorption kinetics satisfactorily; and the rate determining step in Pb^2＋ adsorption onto CB[8] was the external mass transfer step. Equilibrium isotherm study reveals that the Langmuir model gave a better fitting result than Freundlich model. The maximum adsorption capacity calculated by the Langmuir model was 152.67 mg/g for 298 K, 149.70 mg/g for 313 K and 136.42 mg/g for 323 K, respectively. The adsorption is a spontaneous process of exothermic nature. The effect of the adsorbent dosage and the influences of solution pH and co-existing cations were also investigated. The CB[8] was synthesized and characterized by 1H NMR, IR, ESI-MS spectra, SEM-EDAX, Zeta-potential and BET-analysis. The adsorption mechanism was due to the coordination between CB[8] molecule and Pb^2＋ ions.展开更多
Crystalline engineering and heterostructure have attracted much attention as effective strategies to improve the electrocatalytic activity for hydrogen evolution reaction(HER).In this study,a new heterostructure catal...Crystalline engineering and heterostructure have attracted much attention as effective strategies to improve the electrocatalytic activity for hydrogen evolution reaction(HER).In this study,a new heterostructure catalyst(Ru/RuS_(2)@N-rGO)with low crystallinity was fabricated by a simple and low-temperature method for HER in alkaline solution,applying the Na_(2)SO_(4)as S source and polypyrrole as N source.Optimizing through the controllable crystalline engineering and composition ratio of Ru and RuS_(2),the Ru/RuS_(2)@N-rGO heterocatalyst at the calcining 500°C revealed highly efficient HER activity with overpotential 18 mV at a current density 10 mA/cm^(2)and remarkable stability for 24 h in 1.0 mol/L KOH.This work provides a facile and effective method in designing advanced electrocatalysts for HER in the alkaline electrolytes by synergistically structural and component modulations.展开更多
Structural and functional biomimicking of the active site of [NiFe]-hydrogenases can provide helpful hints for designing bioinspired catalysts to replace the expensive noble metal catalysts for H2 generation and uptak...Structural and functional biomimicking of the active site of [NiFe]-hydrogenases can provide helpful hints for designing bioinspired catalysts to replace the expensive noble metal catalysts for H2 generation and uptake.Treatment of dianion [Ni(phma)]2-[H4 phma=N,N’-1,2-phenylenebis(2-mercaptoacetamide)] with [NiCl2(dppp)](dppp=bis(diphenylphosphino)propane) yielded a dinickel product[Ni(phma)(μ-S,S’)Ni(dppp)](1) as the model complex relevant to the active site of [NiFe]-H2 ases.The structure of complex 1 has been characterized by single-crystal X-ray analysis.From cyclic voltammetry and controlled potential electrolysis studies,complex 1 was found to be a moderate electrocatalyst for the H2-evoluting reaction using ClCH2COOH as the proton source.展开更多
Three types of dihalide water clusters [X2（H20）8]2 （X=Cl, Br） and [I2（H20）10]^2- have been observed in cucurbit[6]uril supramolecular systems with same guest. According to the single crystal data and the quantit...Three types of dihalide water clusters [X2（H20）8]2 （X=Cl, Br） and [I2（H20）10]^2- have been observed in cucurbit[6]uril supramolecular systems with same guest. According to the single crystal data and the quantitative theory computation, with the increase of electronegativity of halide ions, dihalide water clusters become more stable. A further comparison of three kinds of guests with different molecule length but the same anions, [p-phenylenediamine salt, hexamethylenediamine salt and N,N＇-hexamethylenebis（pyrazinylbromide）], gives the result that the dihalide water clusters collapse from 2D to 1D with the increase of the lengths.展开更多
A novel[2]pseudorotaxane of cucurbit[6]uril(CB[6])and 1-butyl-3-methyl-imidazolium bromide([C4mim]Br)was synthesized by directly mixing the host and the guest molecules in non-aqueous system.Structural characteri-zati...A novel[2]pseudorotaxane of cucurbit[6]uril(CB[6])and 1-butyl-3-methyl-imidazolium bromide([C4mim]Br)was synthesized by directly mixing the host and the guest molecules in non-aqueous system.Structural characteri-zations of the[2]pseudorotaxane were carried out by 1D,2D NMR and X-ray crystallography techniques both in solution and in crystal structure.The crystal structure demonstrated that CB[6]and[C4mim]Br formed a complex with the ratio 1∶1,in which one guest[C4mim]Br was included inside the CB[6],while two other[C4mim]Br molecules were free and surrounded the[2]pseudorotaxane as solvent molecules,which could stabilize the crystal structure through hydrogen bonds.Moreover,parallel solvent channels consisting by free[C4mim]Br molecules occupied the pores among the frame of the pseudorotaxanes and formed zigzag lines in the crystal structure.[C4mim]Br can serve as not only the guest reactant but also the solvent in the formation of[2]pseudorotaxane for-mation.展开更多
文摘Constructed by selecting appropriate building blocks,covalent organic frameworks(COFs)can be endowed with a variety of specific functions.Herein,we successfully synthesized an imine‐linked H_(2)PReBpy‐COF with the CO_(2) reduction catalyst[ReI(bpy)(CO)_(3)Cl]and the porphyrin photosensitizer as the monomeric building units.The light‐harvesting properties of the porphyrin itself,augmented by the extendedπ‐conjugated planar structure of 2D COF,enable H_(2)PReBpy‐COF the excellent light‐harvesting capability,efficient charge separation,and fast interfacial charge transfer.In addition,a large amount of uniformly distributed[ReI(bpy)(CO)_(3)Cl]units offer H_(2)PReBpy‐COF an excellent activity toward photocatalytic CO_(2) reduction with moderate selectivity and reusability.This study demonstrated a proof of concept in which the advantages of COFs and functional monomers are rationally integrated for photocatalytic solar fuel conversion.
基金support provided by the National Nature Science Foundation of China (Nos. 51208179, 21202037)the Doctor Fund of Henan University of Technology (No. 2013BS066)
文摘In this study, cucurbit[8]uril （CB[8]） was utilized as a kind of new adsorbent to remove Pb^2＋ ions from aqueous solution. With the solution pH increased from 2 to 6, the removal efficiency of adsorption increased from 55.6% to 74.5%correspondingly. The uptake of Pb^2＋ increased rapidly in the initial 30 min, and then the adsorption rate became slower. The Pseudo-second order model could be used to interpret the adsorption kinetics satisfactorily; and the rate determining step in Pb^2＋ adsorption onto CB[8] was the external mass transfer step. Equilibrium isotherm study reveals that the Langmuir model gave a better fitting result than Freundlich model. The maximum adsorption capacity calculated by the Langmuir model was 152.67 mg/g for 298 K, 149.70 mg/g for 313 K and 136.42 mg/g for 323 K, respectively. The adsorption is a spontaneous process of exothermic nature. The effect of the adsorbent dosage and the influences of solution pH and co-existing cations were also investigated. The CB[8] was synthesized and characterized by 1H NMR, IR, ESI-MS spectra, SEM-EDAX, Zeta-potential and BET-analysis. The adsorption mechanism was due to the coordination between CB[8] molecule and Pb^2＋ ions.
基金supported by National Natural Science Foundation of China(Nos.21773184 and 21671158)Key Science and Technology Project of Henan(No.202102210238)+1 种基金Natural Science Foundation of Henan(No.212300410339)Cultivation Program for Young Backbone Teachers in Henan University of Technology(Nos.21420108 and 21420073).
文摘Crystalline engineering and heterostructure have attracted much attention as effective strategies to improve the electrocatalytic activity for hydrogen evolution reaction(HER).In this study,a new heterostructure catalyst(Ru/RuS_(2)@N-rGO)with low crystallinity was fabricated by a simple and low-temperature method for HER in alkaline solution,applying the Na_(2)SO_(4)as S source and polypyrrole as N source.Optimizing through the controllable crystalline engineering and composition ratio of Ru and RuS_(2),the Ru/RuS_(2)@N-rGO heterocatalyst at the calcining 500°C revealed highly efficient HER activity with overpotential 18 mV at a current density 10 mA/cm^(2)and remarkable stability for 24 h in 1.0 mol/L KOH.This work provides a facile and effective method in designing advanced electrocatalysts for HER in the alkaline electrolytes by synergistically structural and component modulations.
基金supported by National Natural Science Foundation of China(Nos.21773184,21671158 and 21601164)Natural Science Foundation of Henan(No.162300410052)Key Science and Technology Project of Henan(No.172102310137)。
文摘Structural and functional biomimicking of the active site of [NiFe]-hydrogenases can provide helpful hints for designing bioinspired catalysts to replace the expensive noble metal catalysts for H2 generation and uptake.Treatment of dianion [Ni(phma)]2-[H4 phma=N,N’-1,2-phenylenebis(2-mercaptoacetamide)] with [NiCl2(dppp)](dppp=bis(diphenylphosphino)propane) yielded a dinickel product[Ni(phma)(μ-S,S’)Ni(dppp)](1) as the model complex relevant to the active site of [NiFe]-H2 ases.The structure of complex 1 has been characterized by single-crystal X-ray analysis.From cyclic voltammetry and controlled potential electrolysis studies,complex 1 was found to be a moderate electrocatalyst for the H2-evoluting reaction using ClCH2COOH as the proton source.
基金We gratefully acknowledge the financial support by the National Natural Science Foundation of China （Nos. 21202037 and 21401044） and Fund of Henan University of Technology （Nos. 2013BS066 and 2014YWQQI4）.
文摘Three types of dihalide water clusters [X2（H20）8]2 （X=Cl, Br） and [I2（H20）10]^2- have been observed in cucurbit[6]uril supramolecular systems with same guest. According to the single crystal data and the quantitative theory computation, with the increase of electronegativity of halide ions, dihalide water clusters become more stable. A further comparison of three kinds of guests with different molecule length but the same anions, [p-phenylenediamine salt, hexamethylenediamine salt and N,N＇-hexamethylenebis（pyrazinylbromide）], gives the result that the dihalide water clusters collapse from 2D to 1D with the increase of the lengths.
基金support by the National Natural Science Foundation of China(Nos.21202037,21401044)Doctor Fund of Henan University of Technology(No.2013BS066).
文摘A novel[2]pseudorotaxane of cucurbit[6]uril(CB[6])and 1-butyl-3-methyl-imidazolium bromide([C4mim]Br)was synthesized by directly mixing the host and the guest molecules in non-aqueous system.Structural characteri-zations of the[2]pseudorotaxane were carried out by 1D,2D NMR and X-ray crystallography techniques both in solution and in crystal structure.The crystal structure demonstrated that CB[6]and[C4mim]Br formed a complex with the ratio 1∶1,in which one guest[C4mim]Br was included inside the CB[6],while two other[C4mim]Br molecules were free and surrounded the[2]pseudorotaxane as solvent molecules,which could stabilize the crystal structure through hydrogen bonds.Moreover,parallel solvent channels consisting by free[C4mim]Br molecules occupied the pores among the frame of the pseudorotaxanes and formed zigzag lines in the crystal structure.[C4mim]Br can serve as not only the guest reactant but also the solvent in the formation of[2]pseudorotaxane for-mation.
