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1.
An Efficient p–n Heterojunction Photocatalyst Constructed from a Coordination Polymer Nanoplate and a Partically Reduced Graphene Oxide for Visible‐Light Hydrogen Production 下载免费PDF全文
Prof. Dr. Xinxin Xu Dr. Tingting Lu Prof. Dr. Xiaoxia Liu Prof. Dr. Xiuli Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(41):14638-14647
A new p–n heterojunction photocatalyst has been synthesized successfully through chemical‐bond‐mediated combination of coordination polymer nanoplates (CPNPs) and partially reduced graphene oxide (PRGO) with a simple colloidal blending process. Photocatalytic H2 production by the p–n heterojunction photocatalyst PRGO / CPNP was investigated under visible‐light irradiation, which illustrates that PRGO / CPNP exhibits a much higher photocatalytic H2 production rate than neat the CPNPs. The improvement of this photocatalytic property can be attributed to the inner electrical field formed in the p–n heterojunction, which impedes recombination of photogenerated electrons and holes. In PRGO / CPNP, the existence of the p–n heterojunction has been confirmed by electrochemical methods clearly. For PRGO / CPNP, the reductive degree of the PRGO has a great influence on the H2 production rate and an ideal condition to get a PRGO / CPNP photocatalyst with higher performance has been obtained. 相似文献
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Peng Wang Baibiao Huang Prof. Dr. Xiaoyang Zhang Prof. Xiaoyan Qin Hao Jin Ying Dai Prof. Dr. Zeyan Wang Jiyong Wei Dr. Jie Zhan Prof. Shaoying Wang Junpeng Wang Myung‐Hwan Whangbo Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(8):1821-1824
Visible improvements : Owing to the plasmon resonance of silver nanoparticles deposited on the surface of AgBr, the newly‐prepared plasmonic photocatalyst Ag§AgBr has a strong absorption in the visible region (see picture) and shows high efficiency in the photodegradation of organic pollutants under visible light.
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Dr. Hua Wang Xiufeng Lang Jian Gao Wei Liu Di Wu Dr. Yongmin Wu Prof. Lin Guo Prof. Jinghong Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(15):4620-4626
Synthesis of inorganic single crystals with exposed high‐reactivity facets is a desirable target in the catalytic chemistry field. Polyhedral AgBr microcrystals with an increased percentage of exposed high‐reactivity {111} facets have been successfully prepared for the first time, and the photocatalytic performance of these microcrystals when used as an AgBr/Ag plasmonic photocatalyst was investigated. The results indicate that the as‐prepared sample has high photocatalytic activity and, under the same measurement conditions, the photodegradation rate of methyl orange dye over these microcrystals is at least four times faster than with other shapes of AgBr/Ag microstructure, as well as 20 times faster than with the highly efficient Ag3PO4 photocatalyst. DFT calculations suggest that the AgBr (111) surface is mainly composed of unsaturated Ag atoms and has a relatively high surface energy, both of which are favorable for enhancing the photocatalytic activity of the AgBr/Ag polyhedron photocatalyst. This work not only provides a highly efficient plasmonic photocatalyst of polyhedral AgBr/Ag microcrystals with an increased percentage of exposed high‐reactivity AgBr {111} facets, but also demonstrates that the shape and crystalline quality of the exposed facets have an important influence on the photocatalytic activities. 相似文献
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Loading of a Coordination Polymer Nanobelt on a Functional Carbon Fiber: A Feasible Strategy for Visible‐Light‐Active and Highly Efficient Coordination‐Polymer‐Based Photocatalysts 下载免费PDF全文
Prof. Dr. Xin‐Xin Xu Dr. Hong‐Yu Yang Dr. Zhen‐Yu Li Prof. Dr. Xiao‐Xia Liu Prof. Dr. Xiu‐Li Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(9):3821-3830
To improve the photocatalytic properties of coordination polymers under irradiation in the visible‐light region, coordination polymer nanobelts (CPNB) were loaded on functional carbon fiber (FCF) through the use of a simple colloidal blending process. The resulting coordination polymer nanobelt loaded functional carbon fiber composite material (CPNB/FCF) exhibited dramatically improved photocatalytic activity for the degradation of rhodamine B (RhB) under visible‐light irradiation. Optical and electrochemical methods illustrated the enhanced photocatalytic activity of CPNB/FCF originated from high separation efficiency of photogenerated electrons and holes on the interface of CPNB and FCF, which was produced by the synergy effect between them. In the composite material, the role of FCF could be described as photosensitizer and good electron transporter. For FCF, the number of functional groups on its surface has a significant influence on the photocatalytic performance of the resulting CPNB/FCF composite material, and an ideal FCF carrier was obtained as a highly efficient CPNB/FCF photocatalyst. CPNB/FCF showed outstanding stability during the degradation of rhodamine B (RhB); thus, the material is suitable for use as a photocatalyst in the treatment of organic dyes in water. 相似文献
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Xingmiao Zhang Haichen Liang Haoze Li Yuan Xia Xiaohang Zhu Liang Peng Wei Zhang Liangliang Liu Tiancong Zhao Changyao Wang Zaiwang Zhao Chin‐Te Hung Moustafa M. Zagho Ahmed A. Elzatahry Wei Li Dongyuan Zhao 《Angewandte Chemie (International ed. in English)》2020,59(8):3287-3293
A universal sequential synthesis strategy in aqueous solution is presented for highly uniform core–shell structured photocatalysts, which consist of a metal sulfide light absorber core and a metal sulfide co‐catalyst shell. We show that the sequential chemistry can drive the formation of unique core–shell structures controlled by the constant of solubility product of metal sulfides. A variety of metal sulfide core–shell structures have been demonstrated, including CdS@CoSx, CdS@MnSx, CdS@NiSx, CdS@ZnSx, CuS@CdS, and more complexed CdS@ZnSx@CoSx. The obtained strawberry‐like CdS@CoSx core–shell structures exhibit a high photocatalytic H2 production activity of 3.92 mmol h?1 and an impressive apparent quantum efficiency of 67.3 % at 420 nm, which is much better than that of pure CdS nanoballs (0.28 mmol h?1), CdS/CoSx composites (0.57 mmol h?1), and 5 %wt Pt‐loaded CdS photocatalysts (1.84 mmol h?1). 相似文献
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Saulius Grigalevicius Michael Forster Stefan Ellinger Katharina Landfester Ullrich Scherf 《Macromolecular rapid communications》2006,27(3):200-202
Summary: The first examples of the dye‐coated semi‐conducting polymer nanoparticles as well as experiments to demonstrate the excitation energy transfer from the excited chromophor of the nanoparticle to the fluorescent dye are described. We have demonstrated that the blue fluorescence of the dye‐coated polyfluorene nanoparticles is only slightly quenched after dye deposition. However, a new emission band of the surface‐bound dye (Rhodamine 6G or Rhodamine TM) appears in the wavelength region of 530–600 nm. These results clearly indicate an effective excitation energy transfer from the excited PF chromophores to the fluorescent dye.
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Nicolas Ramos‐Berdullas Prof. Dr. Marcos Mandado 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(11):3646-3654
Recently, experimental and theoretical determination of electric currents induced by finite bias voltages in p‐xylylene chains attached to gold contacts revealed higher conductance of these systems in comparison with p‐phenylene homologous chains. To gain more insight into the conducting properties of these oligophenyl structures, ab initio studies were carried out on the electronic properties of two different p‐xylylene‐like chains (pX1 and pX2) and the p‐phenylene (pP) chain attached to gold contacts, with molecular formulas AuCH2(C6H4)nCH2Au (n=1–5), Au2C(C6H4)nCAu2 (n=1–5), and Au(C6H4)nAu (n=1–5), respectively. The molecules were subjected to finite bias voltages ranging from 0 to 5 V. Analysis of the intramolecular electron transfer and electron delocalization revealed a completely opposite response to electric perturbation of pX2 in comparison with pX1 and pP. Thus, in pX2 the applied voltage causes an increase in the electron delocalization within the rings together with a large electron transfer and energetic stabilization. On the contrary, the same voltages partially destroy the electron delocalization in pX1 and pP, produce a large local electron polarization in the benzene rings, and a smaller energetic stabilization. These differences can be rationalized in terms of the role played by polarized valence bond structures in the total wave function. Theoretical estimation of the I/V profiles indicates that pX2 chains are much better electronic conductors than pX1 and pP. 相似文献
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Konstantinos Mpoukouvalas Dr. Jianjun Wang Dr. Gerhard Wegner Prof. 《Chemphyschem》2010,11(1):139-148
The dielectric properties of poly(styrene) nanoparticles decorated at their surfaces with poly(styrene sulfonate) [PSS] brushes and subsequently loaded with polypyrrole (PPy) were studied. These film‐forming materials which may serve as hole‐injection layers in organic light‐emitting diodes, exhibit a core–shell‐type morphology with a core of electrically insulating poly(styrene) and a shell consisting of a corona of PSS chains which form the matrix in which the electrically conducting complex of PPy and PSS is embedded. This conducting complex exists in form of domains of nanoscale dimensions. Thin compressed pellets of these nanoparticles were studied using mainly impedance spectroscopy. Measurements were carried out in the temperature range between 123 and 453 K and frequency range from 10?1 to 106 Hz. While earlier studies were centered around the effect of polypyrrole volume fraction on the conductivity films and pellets composed of these nanoparticles, the present study reveals in which way the conductivity can be modified by exchange of the mobile inorganic counter ions of PSS. Besides the free‐acid form (H+), the Li+‐, Na+‐ and Cs+‐salts of PSS were investigated. The PPy volume fraction was the same for all PPy/PSS core–shell nanoparticles. The distance for phonon‐assisted hopping between next‐neighbor polypyrrolium chains is influenced by the presence of these inorganic cations. For all samples containing PPy, a transition from insulating to conducting behavior in the range of 300‐350 K was found. Using the fluctuation‐induced tunneling model, the average tunneling distance, as well as the potential energy barrier separating neighboring conducting grains was estimated. Finally, a detailed analysis of the dielectric spectra suggests the localization length of the charge carriers to be about 0.33 nm. 相似文献
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Zhen Chen Vivian Wing‐Wah Yam 《Angewandte Chemie (International ed. in English)》2020,59(12):4840-4845
The development of size‐selective membranes with well‐defined nanopores towards the precise separation of nanometer‐sized substances is a challenging task to achieve. Here a supramolecular membrane is presented that comprises a highly oriented, honeycomb‐like, 2D supramolecular polymer on a polycarbonate filter support. It enables precise size‐selective sieving of colloidal nanoparticles (NPs). Owing to the uniform parallel‐aligned nanocavities within the 2D supramolecular polymers, the composite membrane shows a high size‐selectivity with a sub‐nanometer accuracy in the cutoff size of about 4.0 nm. In principle, the species of size‐separable particles are unlimited, as demonstrated by quantum dots, noble metal, and metal oxide NPs. This supramolecular membrane combined with filtration advances the potential of NPs in terms of their monochromatic emission and size monodispersity, and also enables rapid removal of small magnetic NP adsorbents that are otherwise difficult to capture. 相似文献
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New microstructured chromium doped poly(p‐toluidine) as a new acid–base indicator and precursor for chromic oxide nanostructured 下载免费PDF全文
New chromium doped poly(p‐toluidine) (Cr‐PPT) was synthesized via chemical oxidative polymerization of p‐toluidine with potassium dichromate as an initiator in acidic aqueous medium. The spectrophotometric behavior of Cr‐PPT in acetone and chloroform as different solvents was investigated. Cr‐PPT exhibits bathochromically red shift at 46‐nm value with the increasing of solvent polarity. The intermolecular charge transfer band peak for Cr‐PPT shifted from 422 nm in low‐polar solvent (chloroform) to high‐polar solvent (acetone) to 468 nm. Optical absorption measurements are used to obtain the energy gap of prepared Cr‐PPT. Cr‐PPT has an optical band gap (Eg = 1.90 to 2.05 eV) that is located in the semiconductor range. Pink color was observed using Cr‐PPT solution in acidic media while it changes sharply to yellow in basic medium. Based on intermolecular charge transfer, the Cr‐PPT was used as acid–base indicator. Cr‐PPT and phenolphthalein (phph) indicator were used for determination of normality of HCl using standard 0.1 N NaOH, the two indicators gave equal end point values. Using Cr‐PPT as a new molecular precursor for the production chromium oxide in nanoscale by thermal decomposition route was studied, and the average size of synthesized Cr2O3 was found in the range of 54–61 nm. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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Constructing Ordered Three‐Dimensional TiO2 Channels for Enhanced Visible‐Light Photocatalytic Performance in CO2 Conversion Induced by Au Nanoparticles 下载免费PDF全文
Dr. Hairong Xue Prof. Dr. Tao Wang Hao Gong Hu Guo Xiaoli Fan Bin Gao Yaya Feng Prof. Dr. Xianguang Meng Prof. Dr. Xianli Huang Prof. Dr. Jianping He 《化学:亚洲杂志》2018,13(5):577-583
As a typical photocatalyst for CO2 reduction, practical applications of TiO2 still suffer from low photocatalytic efficiency and limited visible‐light absorption. Herein, a novel Au‐nanoparticle (NP)‐decorated ordered mesoporous TiO2 (OMT) composite (OMT‐Au) was successfully fabricated, in which Au NPs were uniformly dispersed on the OMT. Due to the surface plasmon resonance (SPR) effect derived from the excited Au NPs, the TiO2 shows high photocatalytic performance for CO2 reduction under visible light. The ordered mesoporous TiO2 exhibits superior material and structure, with a high surface area that offers more catalytically active sites. More importantly, the three‐dimensional transport channels ensure the smooth flow of gas molecules, highly efficient CO2 adsorption, and the fast and steady transmission of hot electrons excited from the Au NPs, which lead to a further improvement in the photocatalytic performance. These results highlight the possibility of improving the photocatalysis for CO2 reduction under visible light by constructing OMT‐based Au‐SPR‐induced photocatalysts. 相似文献
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Heterophase Photocatalysts from Water‐Soluble Conjugated Polyelectrolytes: An Example of Self‐Initiation under Visible Light 下载免费PDF全文
Saman Ghasimi Dr. Simon Prescher Zi Jun Wang Prof. Katharina Landfester Dr. Jiayin Yuan Dr. Kai A. I. Zhang 《Angewandte Chemie (International ed. in English)》2015,54(48):14549-14553
We herein report a new design route to stable, heterophase photocatalysts, which function as highly dispersible conjugated polymer nanoparticles and porous monoliths under visible light in aqueous medium. They were constructed by attachment of the ionic‐liquid species 1‐alkyl‐3‐vinylimidazolium bromide onto the side chains of a photoactive polymer. The structure configuration allows not only photocatalysis in aqueous environment but also a unique self‐initiation radical cross‐linking process to transform the water‐soluble photoactive polymer into a heterophase system, either as nanoparticles or a porous monolith. High photocatalytic activity and reusability of the heterophase system were demonstrated in the degradation of organic dyes and reduction of CrVI into CrIII in water under visible‐light irradiation. 相似文献
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Dr. Jinsuo Gao Xueying Zhang Yan Yang Jun Ke Prof. Xinyong Li Prof. Yaobin Zhang Prof. Feng Tan Prof. Jingwen Chen Prof. Xie Quan 《化学:亚洲杂志》2013,8(5):934-938
Silanol groups on a silica surface affect the activity of immobilized catalysts because they can influence the hydrophilicity/hydrophobicity, matter transfer, or even transition state in a catalytic reaction. Previously, these silanol groups have usually been passivated by using surface‐passivation reagents, such as alkoxysilanes, bis‐silylamine reagents, chlorosilanes, etc., and surface passivation has typically been found in mesoporous‐silicas‐supported molecular catalysts and heteroatomic catalysts. However, this property has rarely been reported in mesoporous‐silicas‐supported metal‐nanoparticle catalysts. Herein, we prepared an almost‐superhydrophobic SBA‐15‐supported gold‐nanoparticle catalyst by using surface passivation, in which the catalytic activity increased more than 14 times for the reduction of nitrobenzene compared with non‐passivated SBA‐15. In addition, this catalyst can selectively catalyze hydrophobic molecules under our experimental conditions, owing to its high (almost superhydrophobic) hydrophobic properties. 相似文献
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Hybrid Coordination Networks Constructed from ɛ‐Keggin‐Type Polyoxometalates and Rigid Imidazole‐Based Bridging Ligands as New Carriers for Noble‐Metal Catalysts 下载免费PDF全文
Xiao‐Jian Yang Dr. Meng Sun Prof. Hong‐Ying Zang Dr. Yuan‐Yuan Ma Dr. Xiao‐Jia Feng Dr. Hua‐Qiao Tan Dr. Yong‐Hui Wang Prof. Yang‐Guang Li 《化学:亚洲杂志》2016,11(6):858-867
Three hybrid coordination networks that were constructed from ?‐Keggin polyoxometalate building units and imidazole‐based bridging ligands were prepared under hydrothermal conditions, that is, H[(Hbimb)2(bimb){Zn4PMoV8MoVI4O40}] ? 6 H2O ( 1 ), [Zn(Hbimbp)(bimbp)3{Zn4PMoV8MoVI4O40}] ? DMF ? 3.5 H2O ( 2 ), and H[Zn2(timb)2(bimba)2Cl2{Zn4PMoV8MoVI4O40}] ? 7 H2O ( 3 ) (bimb=1,4‐bis(1‐imidazolyl)benzene, bimbp=4,4′‐bis(imidazolyl)biphenyl, timb=1,3,5‐tris(1‐imidazolyl)benzene, bimba=3,5‐bis(1‐imidazolyl)benzenamine). All three compounds were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single‐crystal X‐ray diffraction. The mixed valence of the Mo centers was analyzed by XPS spectroscopy and bond‐valence sum calculations. In all three compounds, the ?‐Keggin polyoxometalate (POM) units acted as nodes that were connected by rigid imidazole‐based bridging ligands to form hybrid coordination networks. In compound 1 , 1D zigzag chains extended to form a 3D supramolecular architecture through intermolecular hydrogen‐bonding interactions. Compound 2 consisted of 2D curved sheets, whilst compound 3 contained chiral 2D networks. Because of the intrinsic reducing properties of ?‐Keggin POM species, noble‐metal nanoparticles were loaded onto these POM‐based coordination networks. Thus, compounds 1 – 3 were successfully loaded with Ag nanoparticles, and the corresponding composite materials exhibited high catalytic activities for the reduction of 4‐nitrophenol. 相似文献
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Chang‐Soo Lee Hee Hyun Chang Pan‐Kee Bae Juyeon Jung Bong Hyun Chung 《Macromolecular bioscience》2013,13(3):321-331
Integration of biocompatible silica with a fluorescent polymer (PDDF) and superparamagnetic iron oxide nanoparticles (Fe3O4) to form uniform core–shell nanostructures has the great potential to form particles for use in multimodal bioimaging applications. Core–shell nanoparticles (PDDF/Fe3O4@SiO2) exhibit fluorescent and magnetic properties that are favorable for their use in magnetic separation and guiding applications, as well as optical and magnetic resonance (MR) imaging capabilities. With the biological analysis in an in vitro intracellular permeation and cytotoxicity test, chemical conjugation of the surface using folic acid (FA) molecules can provide the nanoparticles with cell‐targeting properties, localizing the nanoparticles to folate receptors (FRs) on target KB cells that over‐express the FRs.