Energy transfers in two kinds of peripheral light-harvesting complexes （LH2） of Rhodobacter sphaeroides （RS） 601 are studied by using femtosecond pump^probe spectroscopy with tunable laser wavelength at room tempe...Energy transfers in two kinds of peripheral light-harvesting complexes （LH2） of Rhodobacter sphaeroides （RS） 601 are studied by using femtosecond pump^probe spectroscopy with tunable laser wavelength at room temperature. These two complexes are native LH2 （RS601） and green carotenoid mutated LH2 （GM309）. The obtained results demonstrate that, compared with spheroidenes with ten conjugated double bonds in native RS601, carotenoid in GM309 containing neurosporenes with nine conjugated double bonds can lead to a reduction in energy transfer rate in the B800-to-B850 band and the disturbance in the energy relaxation processes within the excitonic B850 band.展开更多
Ultrafast anisotropic decay is a prominent parameter revealing ultrafast energy and electron transfer; however, it is dimcult to be determined reliably owing to the requirement of a simultaneous availability of the pa...Ultrafast anisotropic decay is a prominent parameter revealing ultrafast energy and electron transfer; however, it is dimcult to be determined reliably owing to the requirement of a simultaneous availability of the parallel and perpendieular polarized decay kinetics. Nowadays, any measurement of anisotropic decay is a kind of approach to the exact simultaneity. Here we report a novel method for a synchronous ultrafast anisotropy decay measurement, which can well determine the anisotropy, even at a very early time, as the rising phase of the excitation laser pulse. The anisotropic decay of the B850 in bacteriM light harvesting antenna complex LH2 of rhodobacter sphaeroides in solution at room temperature with coherent excitation is detected by this method, which shows a polarization response time of 30 fs, and the energy transfer from the initial excitation to the bacteriochlorophylls in B850 ring takes about 7Ors. The anisotropic decay that is probed at the red side of the absorption spectrum, such as 880 nm, has an initial value of 0.4, corresponding to simulated emission, while the blue side with an anisotropy of 0.1 contributes to the ground-state bleaching. Our results show that the coherent excitation covering the whole ring might not be realized owing to the symmetry breaking of LH2： from C9 symmetry in membrane to C2 symmetry in solution.展开更多
A photocatalyst of nanometer TiO2/conjugated polymer complex was successfully synthesized and characterized by spectroscopic methods and photocatalytic experiments. The complex photocatalyst could be activated by abso...A photocatalyst of nanometer TiO2/conjugated polymer complex was successfully synthesized and characterized by spectroscopic methods and photocatalytic experiments. The complex photocatalyst could be activated by absorbing both ultraviolet and visible light （λ = 190-800 nm）. Methylene blue （MB） could be degraded more efficiently on the complex photocatalyst than on the TiO2 under natural light. The conjugated polymer played a promoting role in the photocatalytic degradation of MB. The calcination temperature had an important effect in degradation of dye and could be summarized as 260℃ 〉 300 ℃ 〉 340 ℃ 〉 220 ℃ 〉 180 ℃.展开更多
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
A new Pb（Ⅱ） coordination polymer [Pb（L1）（L2）]·1.25H2O has been synthesized with 2-（4-fluorophenyl）-1H-imidazo[4,5-f][1,10]phenanthroline （L1） and sebacic acid （H2L2） under hydrothermal conditions. Cr...A new Pb（Ⅱ） coordination polymer [Pb（L1）（L2）]·1.25H2O has been synthesized with 2-（4-fluorophenyl）-1H-imidazo[4,5-f][1,10]phenanthroline （L1） and sebacic acid （H2L2） under hydrothermal conditions. Crystallographic data： triclinic, space group Pī with a=8.4890（17）, b=12.471（3）, c=14.604（3）, α=67.04（3）, β=74.08（3）, γ=85.80（3）°, V=1368.0（5）3 , Z=1, C58H59F2N8O10.5Pb2 , Mr=1488.51, Dc=1.807g/cm3 , F（000）=729, μ（MoKa）=6.221mm-1 , R=0.0283 and wR=0.0564. The L2 dianions bridge neighboring Pb（Ⅱ） atoms to form a two-dimensional layer structure. The π-π interactions between the L1 ligands of neighboring layers led to a three-dimensional supramolecular architecture. The IR and TGA of the complex have been studied in detail.展开更多
Dye sensitized solar cell（DSSC） is a promising thin film solar cell that has been widely investigated after its birth because of its advantages,such as flexibility,low-cost,easyfabrication and so on[1-3].For DSSCs,s...Dye sensitized solar cell（DSSC） is a promising thin film solar cell that has been widely investigated after its birth because of its advantages,such as flexibility,low-cost,easyfabrication and so on[1-3].For DSSCs,sensitizers play a core role due to their responsibility for the generation of the photo carriers resulted from light absorption and the transfer of the photo-generated electrons into semiconductor photoanodes[4].Keywords：Light-harvesting complex Ⅱ; Anthraquinone 2-carboxylic acid; ZnO; TiO2 nanostructure; Solar cell展开更多
Photochemical reduction of CO2 with H20 into energy-rich chemicals using inexhaustible solar energy is an appealing strategy to simultaneously address the global energy and environmental issues. Earth-abundant metal c...Photochemical reduction of CO2 with H20 into energy-rich chemicals using inexhaustible solar energy is an appealing strategy to simultaneously address the global energy and environmental issues. Earth-abundant metal complexes show promising application in this field due to their easy availability, rich redox valence and tunable property. Great progress has been seen on catalytic reduction of CO2 under visible light illumination employing earth-abundant metal complexes and their hybrids as key contributors, especially for producing CO and HCOOH via the two-electron reduction process. In this minireview, we will summarize and update advances on earth-abundant metal complex-derived photocatalytic system for visible-light driven CO2 photoreduction over the last 5 years. Homogeneous earth-abundant metal complex photocatalysts and earth-abundant metal complex derived hybrid photocatalysts were both presented with focus on efficient improvement strategy.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10274013）.
文摘Energy transfers in two kinds of peripheral light-harvesting complexes （LH2） of Rhodobacter sphaeroides （RS） 601 are studied by using femtosecond pump^probe spectroscopy with tunable laser wavelength at room temperature. These two complexes are native LH2 （RS601） and green carotenoid mutated LH2 （GM309）. The obtained results demonstrate that, compared with spheroidenes with ten conjugated double bonds in native RS601, carotenoid in GM309 containing neurosporenes with nine conjugated double bonds can lead to a reduction in energy transfer rate in the B800-to-B850 band and the disturbance in the energy relaxation processes within the excitonic B850 band.
基金Supported by the National Natural Science Foundation of China under Grant Nos 20925313,21227003,and 11004236the National Basic Research Program of China under Grant No 2009CB930700the Innovation Program of Chinese Academy of Sciences under Grant No KJCX2-YW-W25
文摘Ultrafast anisotropic decay is a prominent parameter revealing ultrafast energy and electron transfer; however, it is dimcult to be determined reliably owing to the requirement of a simultaneous availability of the parallel and perpendieular polarized decay kinetics. Nowadays, any measurement of anisotropic decay is a kind of approach to the exact simultaneity. Here we report a novel method for a synchronous ultrafast anisotropy decay measurement, which can well determine the anisotropy, even at a very early time, as the rising phase of the excitation laser pulse. The anisotropic decay of the B850 in bacteriM light harvesting antenna complex LH2 of rhodobacter sphaeroides in solution at room temperature with coherent excitation is detected by this method, which shows a polarization response time of 30 fs, and the energy transfer from the initial excitation to the bacteriochlorophylls in B850 ring takes about 7Ors. The anisotropic decay that is probed at the red side of the absorption spectrum, such as 880 nm, has an initial value of 0.4, corresponding to simulated emission, while the blue side with an anisotropy of 0.1 contributes to the ground-state bleaching. Our results show that the coherent excitation covering the whole ring might not be realized owing to the symmetry breaking of LH2： from C9 symmetry in membrane to C2 symmetry in solution.
文摘A photocatalyst of nanometer TiO2/conjugated polymer complex was successfully synthesized and characterized by spectroscopic methods and photocatalytic experiments. The complex photocatalyst could be activated by absorbing both ultraviolet and visible light （λ = 190-800 nm）. Methylene blue （MB） could be degraded more efficiently on the complex photocatalyst than on the TiO2 under natural light. The conjugated polymer played a promoting role in the photocatalytic degradation of MB. The calcination temperature had an important effect in degradation of dye and could be summarized as 260℃ 〉 300 ℃ 〉 340 ℃ 〉 220 ℃ 〉 180 ℃.
基金supported by the National Key Basic Research Program of China(973)(2009CB220008)National Natural Science Foundation of China(20711140133,20703067)Fund of Renmin University of China(10XNI007)~~
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Supported by the Institute Foundation of Siping City (No.2009011)
文摘A new Pb（Ⅱ） coordination polymer [Pb（L1）（L2）]·1.25H2O has been synthesized with 2-（4-fluorophenyl）-1H-imidazo[4,5-f][1,10]phenanthroline （L1） and sebacic acid （H2L2） under hydrothermal conditions. Crystallographic data： triclinic, space group Pī with a=8.4890（17）, b=12.471（3）, c=14.604（3）, α=67.04（3）, β=74.08（3）, γ=85.80（3）°, V=1368.0（5）3 , Z=1, C58H59F2N8O10.5Pb2 , Mr=1488.51, Dc=1.807g/cm3 , F（000）=729, μ（MoKa）=6.221mm-1 , R=0.0283 and wR=0.0564. The L2 dianions bridge neighboring Pb（Ⅱ） atoms to form a two-dimensional layer structure. The π-π interactions between the L1 ligands of neighboring layers led to a three-dimensional supramolecular architecture. The IR and TGA of the complex have been studied in detail.
文摘Dye sensitized solar cell（DSSC） is a promising thin film solar cell that has been widely investigated after its birth because of its advantages,such as flexibility,low-cost,easyfabrication and so on[1-3].For DSSCs,sensitizers play a core role due to their responsibility for the generation of the photo carriers resulted from light absorption and the transfer of the photo-generated electrons into semiconductor photoanodes[4].Keywords：Light-harvesting complex Ⅱ; Anthraquinone 2-carboxylic acid; ZnO; TiO2 nanostructure; Solar cell
文摘Photochemical reduction of CO2 with H20 into energy-rich chemicals using inexhaustible solar energy is an appealing strategy to simultaneously address the global energy and environmental issues. Earth-abundant metal complexes show promising application in this field due to their easy availability, rich redox valence and tunable property. Great progress has been seen on catalytic reduction of CO2 under visible light illumination employing earth-abundant metal complexes and their hybrids as key contributors, especially for producing CO and HCOOH via the two-electron reduction process. In this minireview, we will summarize and update advances on earth-abundant metal complex-derived photocatalytic system for visible-light driven CO2 photoreduction over the last 5 years. Homogeneous earth-abundant metal complex photocatalysts and earth-abundant metal complex derived hybrid photocatalysts were both presented with focus on efficient improvement strategy.
