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1.
Souvik Roy Erwin Reisner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(35):12308-12312
The integration of molecular catalysts with low‐cost, solid light absorbers presents a promising strategy to construct catalysts for the generation of solar fuels. Here, we report a photocatalyst for CO2 reduction that consists of a polymeric cobalt phthalocyanine catalyst (CoPPc) coupled with mesoporous carbon nitride (mpg‐CNx) as the photosensitizer. This precious‐metal‐free hybrid catalyst selectively converts CO2 to CO in organic solvents under UV/Vis light (AM 1.5G, 100 mW cm?2, λ>300 nm) with a cobalt‐based turnover number of 90 for CO after 60 h. Notably, the photocatalyst retains 60 % CO evolution activity under visible light irradiation (λ>400 nm) and displays moderate water tolerance. The in situ polymerization of the phthalocyanine allows control of catalyst loading and is key for achieving photocatalytic CO2 conversion. 相似文献
2.
Shufang Ji Yang Qu Tao Wang Yuanjun Chen Guofeng Wang Xue Li Juncai Dong QiuYu Chen Wanying Zhang Zedong Zhang Shiyou Liang Rong Yu Yu Wang Dingsheng Wang Yadong Li 《Angewandte Chemie (International ed. in English)》2020,59(26):10651-10657
The solar‐driven photocatalytic reduction of CO2 (CO2RR) into chemical fuels is a promising route to enrich energy supplies and mitigate CO2 emissions. However, low catalytic efficiency and poor selectivity, especially in a pure‐water system, hinder the development of photocatalytic CO2RR owing to the lack of effective catalysts. Herein, we report a novel atom‐confinement and coordination (ACC) strategy to achieve the synthesis of rare‐earth single erbium (Er) atoms supported on carbon nitride nanotubes (Er1/CN‐NT) with a tunable dispersion density of single atoms. Er1/CN‐NT is a highly efficient and robust photocatalyst that exhibits outstanding CO2RR performance in a pure‐water system. Experimental results and density functional theory calculations reveal the crucial role of single Er atoms in promoting photocatalytic CO2RR. 相似文献
3.
《Journal of separation science》2017,40(15):3114-3119
A simple, fast, sensitive, and low‐cost method was developed for the quantification of nitroaromatic compounds in water samples based on CO2‐assisted liquid‐phase microextraction using a switchable‐hydrophilicity solvent followed by gas chromatography detection. Dipropylamine was used as extraction solvent with switchable hydrophilicity that can be miscible or immiscible upon the addition or removal of CO2 as a reagent. Experimental parameters affecting the extraction efficiency such as the volume of acceptor phase, the volume of donor phase, pH of donor phase, ionic strength, and extraction time were investigated. Under the optimal conditions, detection limits and preconcentration factors were obtained in the ranges of 0.9–1.8 μg/L and 132–138, respectively. Also, the extraction recoveries of water samples were above 88%. Finally, the developed method was successfully applied to the determination of nitroaromatic compounds in real water samples. 相似文献
4.
Ang Li Qian Cao Guangye Zhou Bernhard V. K. J. Schmidt Wenjin Zhu Xintong Yuan Hailing Huo Jinlong Gong Markus Antonietti 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(41):14691-14697
The photocatalytic CO2 reduction reaction (CRR) represents a promising route for the clean utilization of stranded renewable resources, but poor selectivity resulting from the competing hydrogen evolution reaction (HER) in aqueous solution limits its practical applicability. In the present contribution a photocatalyst with hydrophobic surfaces was fabricated. It facilitates an efficient three‐phase contact of CO2 (gas), H2O (liquid), and catalyst (solid). Thus, concentrated CO2 molecules in the gas phase contact the catalyst surface directly, and can overcome the mass‐transfer limitations of CO2, inhibit the HER because of lowering proton contacts, and overall enhance the CRR. Even when loaded with platinum nanoparticles, one of the most efficient HER promotion cocatalysts, the three‐phase photocatalyst maintains a selectivity of 87.9 %. Overall, three‐phase photocatalysis provides a general and reliable method to enhance the competitiveness of the CRR. 相似文献
5.
A Doping Technique that Suppresses Undesirable H2 Evolution Derived from Overall Water Splitting in the Highly Selective Photocatalytic Conversion of CO2 in and by Water
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Prof. Dr. Kentaro Teramura Zheng Wang Dr. Saburo Hosokawa Prof. Dr. Yoshihisa Sakata Prof. Dr. Tsunehiro Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9906-9909
Photocatalytic conversion of CO2 to reduction products, such as CO, HCOOH, HCHO, CH3OH, and CH4, is one of the most attractive propositions for producing green energy by artificial photosynthesis. Herein, we found that Ga2O3 photocatalysts exhibit high conversion of CO2. Doping of Zn species into Ga2O3 suppresses the H2 evolution derived from overall water splitting and, consequently, Zn‐doped, Ag‐modified Ga2O3 exhibits higher selectivity toward CO evolution than bare, Ag‐modified Ga2O3. We observed stoichiometric amounts of evolved O2 together with CO. Mass spectrometry clarified that the carbon source of the evolved CO is not the residual carbon species on the photocatalyst surface, but the CO2 introduced in the gas phase. Doping of the photocatalyst with Zn is expected to ease the adsorption of CO2 on the catalyst surface. 相似文献
6.
Yun Zheng Lihua Lin Bo Wang Prof. Xinchen Wang 《Angewandte Chemie (International ed. in English)》2015,54(44):12868-12884
As a promising two‐dimensional conjugated polymer, graphitic carbon nitride (g‐C3N4) has been utilized as a low‐cost, robust, metal‐free, and visible‐light‐active photocatalyst in the field of solar energy conversion. This Review mainly describes the latest advances in g‐C3N4 photocatalysts for water splitting. Their application in CO2 conversion, organosynthesis, and environmental purification is also briefly discussed. The methods to modify the electronic structure, nanostructure, crystal structure, and heterostructure of g‐C3N4, together with correlations between its structure and performance are illustrated. Perspectives on the challenges and opportunities for the future exploration of g‐C3N4 photocatalysts are provided. This Review will promote the utilization of g‐C3N4 materials in the fields of photocatalysis, energy conversion, environmental remediation, and sensors. 相似文献
7.
Jane J. Leung Julian A. Vigil Julien Warnan Esther EdwardesMoore Erwin Reisner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(23):7779-7783
A series of copolymers comprising a terpyridine ligand and various functional groups were synthesized toward integrating a Co‐based molecular CO2 reduction catalyst. Using porous metal oxide electrodes designed to host macromolecules, the Co‐coordinated polymers were readily immobilized via phosphonate anchoring groups. Within the polymeric matrix, the outer coordination sphere of the Co terpyridine catalyst was engineered using hydrophobic functional moieties to improve CO2 reduction selectivity in the presence of water. Electrochemical and photoelectrochemical CO2 reduction were demonstrated with the polymer‐immobilized hybrid cathodes, with a CO:H2 product ratio of up to 6:1 compared to 2:1 for a corresponding “monomeric” Co terpyridine catalyst. This versatile platform of polymer design demonstrates promise in controlling the outer‐sphere environment of synthetic molecular catalysts, analogous to CO2 reductases. 相似文献
8.
Colin A. Scholes Jianyong Jin Geoff W. Stevens Sandra E. Kentish 《Journal of Polymer Science.Polymer Physics》2015,53(10):719-728
Highly permeable glassy polymeric membranes based on poly (1‐trimethylsilyl‐1‐propyne) (PTMSP) and a polymer of intrinsic porosity (PIM‐1) were investigated for water sorption, water permeability and the separation of CO2 from N2 under humid mixed gas conditions. The water sorption isotherms for both materials followed behavior indicative of multilayer adsorption within the microvoids, with PIM‐1 registering a significant water uptake at very high water activities. Analysis of the sorption isotherms using a modified dual sorption model which accounts for such multilayer effects gave Langmuir affinity constants more consistent with lighter gases than the use of the standard dual mode approach. The water permeability through PTMSP and PIM‐1 was comparable over the water activities studied, and could be successfully model ed through a dual mode sorption model with a concentration dependent diffusivity. The water permeability through both membranes as a function of temperature was also measured, and found to be at a minimum at 80 ° C for PTMSP and 70 °C for PIM‐1. This temperature dependence is a function of reducing water solubility in both membranes with increasing temperature countered by increasing water diffusivity. The CO2 ‐ N2 mixed gas permeabilities through PTMSP and PIM‐1 were also measured and model ed through dual mode sorption theory. Introducing water vapour further reduced both the CO2 and N2 permeabilities. The plasticization potential of water in PTMSP was determined and indicated water swelled the membrane increasing CO2 and N2 diffusivity, while for PIM‐1 a negative potential implied that water filling of the microvoids hampered CO2 and N2 diffusion through the membrane. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 719–728 相似文献
9.
A Long‐Lived Mononuclear Cyclopentadienyl Ruthenium Complex Grafted onto Anatase TiO2 for Efficient CO2 Photoreduction
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Haowei Huang Jinjin Lin Dr. Gangbei Zhu Prof. Yuxiang Weng Prof. Xuxu Wang Prof. Xianzhi Fu Prof. Jinlin Long 《Angewandte Chemie (International ed. in English)》2016,55(29):8314-8318
This work shows a novel artificial donor–catalyst–acceptor triad photosystem based on a mononuclear C5H5‐RuH complex oxo‐bridged TiO2 hybrid for efficient CO2 photoreduction. An impressive quantum efficiency of 0.56 % for CH4 under visible‐light irradiation was achieved over the triad photocatalyst, in which TiO2 and C5H5‐RuH serve as the electron collector and CO2‐reduction site and the photon‐harvester and water‐oxidation site, respectively. The fast electron injection from the excited Ru2+ cation to TiO2 in ca. 0.5 ps and the slow backward charge recombination in half‐life of ca. 9.8 μs result in a long‐lived D+–C–A? charge‐separated state responsible for the solar‐fuel production. 相似文献
10.
Hailong Che Meng Huo Liao Peng Tommy Fang Na Liu Prof. Lin Feng Prof. Yen Wei Prof. Jinying Yuan 《Angewandte Chemie (International ed. in English)》2015,54(31):8934-8938
Responsive polymer interfacial materials are ideal candidates for controlling surface wetting behavior. Here we developed smart nanostructured electrospun polymer membranes which are capable of switching oil/water wettability using CO2 as the trigger. In particular, the combination of CO2‐responsiveness and porous nanostructure enables the as‐prepared membranes to be used as a novel oil/water on–off switch. We anticipate that the promising versatility and simplicity of this system would not only open up a new way of surface wettability change regulation by gas, but also have obvious advantages in terms of highly controlled oil/water separation and CO2 applications. 相似文献
11.
A visible light active p-n heterojunction photocatalyst was synthesized successfully through in-situ chemical oxidation copolymerization of aniline (ANI) and diphenylamine-4-sulfonate (DPAS) with the existence of coordination polymer nanorod (CPNR) under initiation of ammonium persulfate (APS). Compared with neat coordination polymer nanorod, the resulted p-n heterojunction photocatalyst exhibits higher H2 generationrate under visible light irradiation. In this heterojunction photocatalyst, as a p-type semiconductor possessing suitable energy levels with coordination polymer nanorod, poly-(aniline-co-N-(4-sulfophenyl)-aniline) (PAPSA) forms p-n heterojunction with n-type coordination polymer nanorod, the inner electric field of p-n heterojunction accelerates the separation of electrons and holes, which enhances H2 production performance. Furthermore, the influence of concentration ratio between DPAS and ANI on photocatalytic property of the p-n heterojunction photocatalyst was discussed and a reasonable condition to fabricate photocatalyst with high H2 generationrate had been obtained. During photocatalytic water splitting H2 generation, the p-n heterojunction photocatalyst exhibited outstanding stability. 相似文献
12.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(31):9254-9258
The utilization of CO2 in Li‐CO2 batteries is attracting extensive attention. However, the poor rechargeability and low applied current density have remained the Achilles’ heel of this energy device. The gel polymer electrolyte (GPE), which is composed of a polymer matrix filled with tetraglyme‐based liquid electrolyte, was used to fabricate a rechargeable Li‐CO2 battery with a carbon nanotube‐based gas electrode. The discharge product of Li2CO3 formed in the GPE‐based Li‐CO2 battery exhibits a particle‐shaped morphology with poor crystallinity, which is different from the contiguous polymer‐like and crystalline discharge product in conventional Li‐CO2 battery using a liquid electrolyte. Accordingly, the GPE‐based battery shows much improved electrochemical performance. The achieved cycle life (60 cycles) and rate capability (maximum applied current density of 500 mA g−1) are much higher than most of previous reports, which points a new way to develop high‐performance Li‐CO2 batteries. 相似文献
13.
Yun Zheng Lihua Lin Xiangju Ye Fangsong Guo Prof. Xinchen Wang 《Angewandte Chemie (International ed. in English)》2014,53(44):11926-11930
Graphitic carbon nitride can be imprinted with a twisted hexagonal rod‐like morphology by a nanocasting technique using chiral silicon dioxides as templates. The helical nanoarchitectures promote charge separation and mass transfer of carbon nitride semiconductors, enabling it to act as a more efficient photocatalyst for water splitting and CO2 reduction than the pristine carbon nitride polymer. This is to our knowledge a unique example of chiral graphitic carbon nitride that features both left‐ and right‐handed helical nanostructures and exhibits unique optical activity to circularly polarized light at the semiconductor absorption edge as well as photoredox activity for solar‐to‐chemical conversion. Such helical nanostructured polymeric semiconductors are envisaged to hold great promise for a range of applications that rely on such semiconductor properties as well as chirality for photocatalysis, asymmetric catalysis, chiral recognition, nanotechnology, and chemical sensing. 相似文献
14.
Amine‐Appended Hierarchical Ca‐A Zeolite for Enhancing CO2/CH4 Selectivity of Mixed‐Matrix Membranes
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An amine‐appended hierarchical Ca‐A zeolite that can selectively capture CO2 was synthesized and incorporated into inexpensive membrane polymers, in particular polyethylene oxide and Matrimid, to design mixed‐matrix membranes with high CO2/CH4 selectivities. Binary mixture permeation testing reveals that amine‐appended mesoporous Ca‐A is highly effective in improving CO2/CH4 selectivity of polymeric membranes. In particular, the CO2/CH4 selectivity of the polyethylene oxide membrane increases from 15 to 23 by incorporating 20 wt % amine‐appended Ca‐A zeolite. Furthermore, the formation of filler/polymer interfacial defects, which is typically found in glassy polymer‐zeolite pairs, is inhibited owing to the interaction between the amine groups on the external surface of zeolites and polymer chains. Our results suggest that the amine‐appended hierarchial Ca‐A, which was utilized in membrane fabrication for the first time, is a good filler material for fabricating a CO2‐selective mixed‐matrix membrane with defect‐free morphology. 相似文献
15.
Youn Jeong Jang Dr. Jae Young Kim Won Yong Kim Prof. Jeong Kon Seo Prof. Sungjee Kim Prof. Kun‐Hong Lee Prof. Jae Sung Lee 《Angewandte Chemie (International ed. in English)》2014,53(23):5852-5857
As a photocathode for CO2 reduction, zinc‐blende zinc telluride (ZnTe) was directly formed on a Zn/ZnO nanowire substrate by a simple dissolution–recrystallization mechanism without any surfactant. With the most negative conduction‐band edge among p‐type semiconductors, this new photocatalyst showed efficient and stable CO formation in photoelectrochemical CO2 reduction at ?0.2–?0.7 V versus RHE without a sacrificial reagent. 相似文献
16.
Yuan Li Eun J. Park Kwon T. Lim Keith P. Johnston Peter F. Green 《Journal of Polymer Science.Polymer Physics》2007,45(11):1313-1324
It has recently been shown that thin polymer films in the nanometer thickness range exhibit anomalous swelling maxima in supercritical CO2 (Sc‐Co2) in the vicinity of the critical point of CO2. The adsorption isotherm of CO2 on carbon black, silica surfaces, porous zeolites, and other surfaces, is known to exhibit anomalous maxima under similar CO2 conditions. It is believed that because CO2 possesses a low cohesive energy density, there would be an excess amount of CO2 at the surfaces of these materials and hence the CO2/polymer interface. This might cause excess CO2 in the polymer films near the free surface, and hence the swelling anomaly. In addition, an excess of CO2 would reside at the polymer/substrate and polymer/CO2 interfaces for entropic reasons. These interfacial effects, as have been suggested, should account for an overall excess of CO2 in a thin polymer film compared to the bulk, and would be responsible for the anomalous swelling. In this study, we use in situ spectroscopic ellipsometry to investigate the role of interfaces on the anomalous swelling of polymer thin films of varying initial thicknesses, h0, exposed to Sc‐CO2. We examined three homopolymers, poly(1,1′‐dihydroperflurooctyl methacrylate) (PFOMA), polystyrene (PS), poly(ethylene oxide) (PEO), that exhibit very different interactions with Sc‐CO2, and the diblock copolymer of PS‐b‐PFOMA. We show that the anomalous swelling cannot be solely explained by the excess adsorption of CO2 at interfaces. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1313–1324, 2007 相似文献
17.
Overall Water Splitting on the Transition‐Metal Oxynitride Photocatalyst LaMg1/3Ta2/3O2N over a Large Portion of the Visible‐Light Spectrum
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Dr. Chengsi Pan Dr. Tsuyoshi Takata Prof. Kazunari Domen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(5):1854-1862
One of the main targets of studies on water splitting photocatalysts is to develop semiconductor materials with narrower bandgaps capable of overall water splitting for efficient harvesting of solar energy. A series of transition‐metal oxynitrides, LaMgxTa1?xO1+3xN2?3x (x≥1/3), with a complex perovskite structure was reported as the first example of overall water splitting operable at up to 600 nm. The photocatalytic behavior of LaMg1/3Ta2/3O2N was investigated in detail in order to optimize photocatalyst preparation and water‐splitting activity. Various attempts exploring photocatalyst preparation steps, that is, cocatalyst selection, coating material and method, and synthesis method for the oxide precursor, revealed photocatalyst structures necessary for achieving overall water splitting. Careful examination of photocatalyst preparation procedures likely enhanced the quality of the produced photocatalyst, leading to a more homogeneous coating quality and semiconductor particles with fewer defects. Thus, the photocatalytic activity for water splitting on LaMg1/3Ta2/3O2N was largely enhanced. 相似文献
18.
Revealing the Transient Concentration of CO2 in a Mixed‐Matrix Membrane by IR Microimaging and Molecular Modeling
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Seungtaik Hwang Dr. Rocio Semino Dr. Beatriz Seoane Marufa Zahan Dr. Christian Chmelik Dr. Rustem Valiullin Dr. Marko Bertmer Prof. Jürgen Haase Prof. Freek Kapteijn Prof. Jorge Gascon Prof. Guillaume Maurin Prof. Jörg Kärger 《Angewandte Chemie (International ed. in English)》2018,57(18):5156-5160
Through IR microimaging the spatially and temporally resolved development of the CO2 concentration in a ZIF‐8@6FDA‐DAM mixed matrix membrane (MMM) was visualized during transient adsorption. By recording the evolution of the CO2 concentration, it is observed that the CO2 molecules propagate from the ZIF‐8 filler, which acts as a transport “highway”, towards the surrounding polymer. A high‐CO2‐concentration layer is formed at the MOF/polymer interface, which becomes more pronounced at higher CO2 gas pressures. A microscopic explanation of the origins of this phenomenon is suggested by means of molecular modeling. By applying a computational methodology combining quantum and force‐field based calculations, the formation of microvoids at the MOF/polymer interface is predicted. Grand canonical Monte Carlo simulations further demonstrate that CO2 tends to preferentially reside in these microvoids, which is expected to facilitate CO2 accumulation at the interface. 相似文献
19.
Joseph R. Royer Yvon J. Gay Joseph M. Desimone Saad A. Khan 《Journal of Polymer Science.Polymer Physics》2000,38(23):3168-3180
A high‐pressure extrusion slit die rheometer was constructed to measure the viscosity of polymer melts plasticized by liquid and supercritical CO2. A novel gas injection system was devised to accurately meter the follow of CO2 into the extruder barrel. Measurements of pressure drop, within the die, confirm the presence of a one‐phase mixture and a fully developed flow during viscosity measurements. Experimental measurements of viscosity as a function of shear rate, pressure, temperature, and CO2 concentration were conducted for three commercial polystyrene melts. The CO2 was shown to be an effective plasticizer for polystyrene, lowering the viscosity of the polymer melt by as much as 80%, depending of the process conditions and CO2 concentration. Existing theories for viscoelastic scaling of polymer melts and the prediction of Tg depression by a diluent were used to develop a free volume model for predicting the effects of CO2 concentration and pressure on polymer melt rheology. The free volume model, dependent only on material parameters of the polymer melt and pure CO2, was shown to accurately collapse the experimental data onto a single master curve independent of pressure and CO2 concentration for each of the three polystyrene samples. This model constitutes a simple predictive set of equations to quantify the effects of gas‐induced plasticization on molten polymer systems. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 3168–3180, 2000 相似文献
20.
A Complex Perovskite‐Type Oxynitride: The First Photocatalyst for Water Splitting Operable at up to 600 nm
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Dr. Chengsi Pan Dr. Tsuyoshi Takata Mamiko Nakabayashi Dr. Takao Matsumoto Prof. Naoya Shibata Prof. Yuichi Ikuhara Prof. Kazunari Domen 《Angewandte Chemie (International ed. in English)》2015,54(10):2955-2959
One of the simplest methods for splitting water into H2 and O2 with solar energy entails the use of a particulate‐type semiconductor photocatalyst. To harness solar energy efficiently, a new water‐splitting photocatalyst that is active over a wider range of the visible spectrum has been developed. In particular, a complex perovskite‐type oxynitride, LaMgxTa1?xO1+3xN2?3x (x≥1/3), can be employed for overall water splitting at wavelengths of up to 600 nm. Two effective strategies for overall water splitting were developed. The first entails the compositional fine‐tuning of a photocatalyst to adjust the bandgap energy and position by forming a series of LaMgxTa1?xO1+3xN2?3x solid solutions. The second method is based on the surface coating of the photocatalyst with a layer of amorphous oxyhydroxide to control the surface redox reactions. By combining these two strategies, the degradation of the photocatalyst and the reverse reaction could be prevented, resulting in successful overall water splitting. 相似文献