TY - JOUR A1 - Zhang, T. A1 - Spitz, Christian A1 - Antonietti, Markus A1 - Faul, C. F. T1 - Highly photoluminescent polyoxometaloeuropate-surfactant complexes by ionic self-assembly N2 - Facile organization of the inorganic sandwiched heteropolytungstomolybdate K-13[Eu(SiW9Mo2O39)(2)] (E) into highly ordered supramolecular nanostructured materials by complexation with a series of cationic surfactants is achieved by the ionic self-assembly (ISA) route. The structure and phase behavior of the complexes were examined by IR spectroscopy, differential scanning calorimetry, optical microscopy, and small- and wide-angle X-ray scattering. This class of materials shows a number of interesting physicochemical properties, namely liquid-crystalline phases (both thermotropic and lyotropic) and strong photoluminescence. The photophysical behavior (fluorescence spectra, fluorescence lifetimes, fluorescence quantum yield) of the complexes differs widely in solid powders, films, and solutions. The amphiphilic cationic surfactants not only play a structural role but also have a strong influence on the photophysical properties of E. The photophysical behavior of E can in this way be easily modified by its organizational motifs Y1 - 2005 ER - TY - JOUR A1 - Sonnenburg, Kirstin A1 - Adelhelm, Philipp A1 - Antonietti, Markus A1 - Smarsly, Bernd A1 - Nöske, Robert A1 - Strauch, Peter T1 - Synthesis and characterization of SiC materials with hierarchical porosity obtained by replication techniques N2 - Porous silicon carbide monoliths were obtained using the infiltration of preformed SiO2 frameworks with appropriate carbon precursors such as mesophase pitch. The initial SiO2 monoliths possessed a hierarchical pore system, composed of an interpenetrating bicontinuous macropore structure and 13 nm mesopores confined in the macropore walls. After carbonization, further heat treatment at ca. 1400 degrees C resulted in the formation of a SiC-SiO2 composite, which was converted into a porous SiC monolith by post-treatment with ammonium fluoride solution. The resulting porous SiC featured high crystallinity, high chemical purity and showed a surface area of 280 m(2) g(-1) and a pore volume of 0.8 ml g(-1) Y1 - 2006 UR - http://pubs.rsc.org/en/Content/ArticleLanding/2006/CP/b604819f U6 - https://doi.org/10.1039/B604819F ER - TY - JOUR A1 - Men, Yongiun A1 - Siebenbürger, Miriam A1 - Qiu, Xunlin A1 - Antonietti, Markus A1 - Yuan, Jiayin T1 - Low fractions of ionic liquid or poly(ionic liquid) can activate polysaccaride biomass into shaped, flexible and fire-retardant porous carbons N2 - Sugar-based molecules and polysaccharide biomass can be turned into porous functional carbonaceous products at comparably low temperatures of 400 °C under a nitrogen atmosphere in the presence of an ionic liquid (IL) or a poly(ionic liquid) (PIL). The IL and PIL act as "activation agents" with own structural contribution, and effectively promote the conversion and pore generation in the biomaterials even at a rather low doping ratio (7 wt%). In addition, this "induced carbonization" and pore forming phenomenon enables the preservation of the biotemplate shape to the highest extent and was employed to fabricate shaped porous carbonaceous materials from carbohydrate-based biotemplates, exemplified here with cellulose filter membranes, coffee filter paper and natural cotton. These carbonized hybrids exhibit comparably good mechanical properties, such as bendability of membranes or shape recovery of foams. Moreover, the nitrogen atoms incorporated in the final products from the IL/PIL precursors further improve the oxidation stability in the fire-retardant tests. Y1 - 2013 UR - http://pubs.rsc.org/en/content/articlepdf/2013/ta/c3ta12302b U6 - https://doi.org/10.1039/c3ta12302b ER - TY - JOUR A1 - Men, Yongjun A1 - Siebenbürger, Miriam A1 - Qiu, Xunlin A1 - Antonietti, Markus A1 - Yuan, Jiayin T1 - Low fractions of ionic liquid or poly(ionic liquid) can activate polysaccharide biomass into shaped, flexible and fire-retardant porous carbons JF - Journal of materials chemistry : A, Materials for energy and sustainability N2 - Sugar-based molecules and polysaccharide biomass can be turned into porous functional carbonaceous products at comparably low temperatures of 400 degrees C under a nitrogen atmosphere in the presence of an ionic liquid (IL) or a poly(ionic liquid) (PIL). The IL and PIL act as "activation agents" with own structural contribution, and effectively promote the conversion and pore generation in the biomaterials even at a rather low doping ratio (7 wt%). In addition, this "induced carbonization" and pore forming phenomenon enables the preservation of the biotemplate shape to the highest extent and was employed to fabricate shaped porous carbonaceous materials from carbohydrate-based biotemplates, exemplified here with cellulose filter membranes, coffee filter paper and natural cotton. These carbonized hybrids exhibit comparably good mechanical properties, such as bendability of membranes or shape recovery of foams. Moreover, the nitrogen atoms incorporated in the final products from the IL/PIL precursors further improve the oxidation stability in the fire-retardant tests. Y1 - 2013 U6 - https://doi.org/10.1039/c3ta12302b SN - 2050-7488 VL - 1 IS - 38 SP - 11887 EP - 11893 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Shalom, Menny A1 - Inal, Sahika A1 - Fettkenhauer, Christian A1 - Neher, Dieter A1 - Antonietti, Markus T1 - Improving Carbon Nitride Photocatalysis by Supramolecular Preorganization of Monomers JF - Journal of the American Chemical Society N2 - Here we report a new and simple synthetic pathway to form ordered, hollow carbon nitride structures, using a cyanuric acid melamine (CM) complex in ethanol as a starting product. A detailed analysis of the optical and photocatalytic properties shows that optimum hollow carbon nitride structures are formed after 8 h of condensation. For this condensation time, we find a significantly reduced fluorescence intensity and lifetime, indicating the formation of new, nonradiative deactivation pathways, probably involving charge-transfer processes. Enhanced charge transfer is seen as well from a drastic increase of the photocatalytic activity in the degradation of rhodamine B dye, which is shown to proceed via photoinduced hole transfer. Moreover, we show that various CM morphologies can be obtained using different solvents, which leads to diverse ordered carbon nitride architectures. In all cases, the CM-C3N4 structures exhibited superior photocatalytic activity compared to the bulk material. The utilization of CM hydrogen-bonded complexes opens new opportunities for the significant improvement of carbon nitride synthesis, structure, and optical properties toward an efficient photoactive material for catalysis. Y1 - 2013 U6 - https://doi.org/10.1021/ja402521s SN - 0002-7863 VL - 135 IS - 19 SP - 7118 EP - 7121 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Wirth, Jonas A1 - Neumann, Rainer A1 - Antonietti, Markus A1 - Saalfrank, Peter T1 - Adsorption and photocatalytic splitting of water on graphitic carbon nitride: a combined first principles and semiempirical study JF - Physical chemistry, chemical physics : a journal of European Chemical Societies N2 - Graphitic carbon nitride, g-C3N4, is a promising organic photo-catalyst for a variety of redox reactions. In order to improve its efficiency in a systematic manner, however, a fundamental understanding of the microscopic interaction between catalyst, reactants and products is crucial. Here we present a systematic study of water adsorption on g-C3N4 by means of density functional theory and the density functional based tight-binding method as a prerequisite for understanding photocatalytic water splitting. We then analyze this prototypical redox reaction on the basis of a thermodynamic model providing an estimate of the overpotential for both water oxidation and H+ reduction. While the latter is found to occur readily upon irradiation with visible light, we derive a prohibitive overpotential of 1.56 eV for the water oxidation half reaction, comparing well with the experimental finding that in contrast to H-2 production O-2 evolution is only possible in the presence of oxidation cocatalysts. Y1 - 2014 U6 - https://doi.org/10.1039/c4cp02021a SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 30 SP - 15917 EP - 15926 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Wirth, Jonas A1 - Neumann, Rainer A1 - Antonietti, Markus A1 - Saalfrank, Peter T1 - Adsorption and photocatalytic splitting of water on graphitic carbon nitride BT - a combined first principles and semiempirical study JF - physical chemistry, chemical physics : PCCP N2 - Graphitic carbon nitride, g-C₃N₄, is a promising organic photo-catalyst for a variety of redox reactions. In order to improve its efficiency in a systematic manner, however, a fundamental understanding of the microscopic interaction between catalyst, reactants and products is crucial. Here we present a systematic study of water adsorption on g-C₃N₄ by means of density functional theory and the density functional based tight-binding method as a prerequisite for understanding photocatalytic water splitting. We then analyze this prototypical redox reaction on the basis of a thermodynamic model providing an estimate of the overpotential for both water oxidation and H⁺ reduction. While the latter is found to occur readily upon irradiation with visible light, we derive a prohibitive overpotential of 1.56 eV for the water oxidation half reaction, comparing well with the experimental finding that in contrast to H₂ production O₂ evolution is only possible in the presence of oxidation cocatalysts. KW - initio molecular-dynamics KW - augmented-wave method KW - visible-light KW - tight-binding KW - transition KW - oxidation KW - photooxidation KW - simulations KW - reduction KW - hydrogen Y1 - 2014 U6 - https://doi.org/10.1039/c4cp02021a SN - 1463-9076 SN - 1463-9084 VL - 2014 IS - 16 SP - 15917 EP - 15926 ER - TY - JOUR A1 - Brosnan, Sarah M. A1 - Schlaad, Helmut A1 - Antonietti, Markus T1 - Aqueous Self-Assembly of Purely Hydrophilic Block Copolymers into Giant Vesicles JF - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition N2 - Self-assembly of macromolecules is fundamental to life itself, and historically, these systems have been primitively mimicked by the development of amphiphilic systems, driven by the hydrophobic effect. Herein, we demonstrate that self-assembly of purely hydrophilic systems can be readily achieved with similar ease and success. We have synthesized double hydrophilic block copolymers from polysaccharides and poly(ethylene oxide) or poly(sarcosine) to yield high molar mass diblock copolymers through oxime chemistry. These hydrophilic materials can easily assemble into nanosized (<500nm) and microsized (>5m) polymeric vesicles depending on concentration and diblock composition. Because of the solely hydrophilic nature of these materials, we expect them to be extraordinarily water permeable systems that would be well suited for use as cellular mimics. KW - block copolymers KW - polymersomes KW - polysaccharides KW - self-assembly KW - vesicles Y1 - 2015 U6 - https://doi.org/10.1002/anie.201502100 SN - 1433-7851 SN - 1521-3773 VL - 54 IS - 33 SP - 9715 EP - 9718 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Kirchhecker, Sarah A1 - Tröger-Müller, Steffen A1 - Bake, Sebastian A1 - Antonietti, Markus A1 - Taubert, Andreas A1 - Esposito, Davido T1 - Renewable pyridinium ionic liquids from the continuous hydrothermal decarboxylation of furfural-amino acid derived pyridinium zwitterions JF - Green chemistry N2 - Fully renewable pyridinium ionic liquids were synthesised via the hydrothermal decarboxylation of pyridinium zwitterions derived from furfural and amino acids in flow. The functionality of the resulting ionic liquid (IL) can be tuned by choice of different amino acids as well as different natural carboxylic acids as the counterions. A representative member of this new class of ionic liquids was successfully used for the synthesis of ionogels and as a solvent for the Heck coupling. Y1 - 2015 U6 - https://doi.org/10.1039/c5gc00913h SN - 1463-9262 SN - 1463-9270 VL - 8 IS - 17 SP - 4151 EP - 4156 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Kirchhecker, Sarah A1 - Tröger-Müller, Steffen A1 - Bake, Sebastian A1 - Antonietti, Markus A1 - Taubert, Andreas A1 - Esposito, Davide T1 - Renewable pyridinium ionic liquids from the continuous hydrothermal decarboxylation of furfural-amino acid derived pyridinium zwitterions JF - Green chemistry : an international journal and green chemistry resource N2 - Fully renewable pyridinium ionic liquids were synthesised via the hydrothermal decarboxylation of pyridinium zwitterions derived from furfural and amino acids in flow. The functionality of the resulting ionic liquid (IL) can be tuned by choice of different amino acids as well as different natural carboxylic acids as the counter-ions. A representative member of this new class of ionic liquids was successfully used for the synthesis of ionogels and as a solvent for the Heck coupling. Y1 - 2015 U6 - https://doi.org/10.1039/c5gc00913h SN - 1463-9262 SN - 1463-9270 VL - 17 IS - 8 SP - 4151 EP - 4156 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Sung, Jian-Ke A1 - Kochovski, Zdravko A1 - Zhang, Wei-Yi A1 - Kirmse, Holm A1 - Lu, Yan A1 - Antonietti, Markus A1 - Yuan, Jiayin T1 - General Synthetic Route toward Highly Dispersed Metal Clusters Enabled by Poly(ionic liquid)s JF - Journal of the American Chemical Society N2 - The ability to synthesize a broad spectrum of metal clusters (MCs) with their size controllable on a subnanometer scale presents an enticing prospect for exploring nanosize-dependent properties. Here we report an innovative design of a capping agent from a polytriazolium poly(ionic liquid) (PIL) in a vesicular form in solution that allows for crafting a variety of MCs including transition metals, noble metals, and their bimetallic alloy with precisely controlled sizes (similar to 1 nm) and record-high catalytic performance. The ultrastrong stabilization power is a result of an unusual synergy between the conventional binding sites in the heterocyclic cations in PIL and an in situ generated polycarbene structure induced simultaneously to the reduction reaction. Y1 - 2017 U6 - https://doi.org/10.1021/jacs.7b03357 SN - 0002-7863 VL - 139 SP - 8971 EP - 8976 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Lee, Hui-Chun A1 - Hwang, Jongkook A1 - Schilde, Uwe A1 - Antonietti, Markus A1 - Matyjaszewski, Krzysztof A1 - Schmidt, Bernhard V. K. J. T1 - Toward ultimate control of radical polymerization BT - functionalized metal-organic frameworks as a robust environment for Metal-Catalyzed Polymerizations JF - Chemistry of materials : a publication of the American Chemical Society N2 - Herein, an approach via combination of confined porous textures and reversible deactivation radical polymerization techniques is proposed to advance synthetic polymer chemistry, i.e., a connection of metal-organic frameworks (MOFs) and activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Zn-2(benzene-1,4-dicarboxylate)2(1,4-diazabicyclo[2.2.2]-octane) [Zn-2(bdc)(2)(dabco)] is utilized as a reaction environment for polymerization of various methacrylate monomers (methyl, ethyl, benzyl, and isobornyl methacrylate) in a confined nanochannel, resulting in polymers with control over dispersity, end functionalities, and tacticity with respect to distinct molecular size. To refine and reconsolidate the compartmentation effect on polymer regularity, initiator-functionalized Zn MOF was synthesized via cocrystallization with an initiator-functionalized ligand, 2-(2-bromo-2-methylpropanamido)-1,4-benzenedicarboxylate (Brbdc), in different ratios (10%, 20%, and 50%). Through the embedded initiator, surface-initiated ARGET ATRP was directly initiated from the walls of the nanochannels. The obtained polymers had a high molecular weight up to 392 000. Moreover, a significant improvement in end-group functionality and stereocontrol was observed, entailing polymers with obvious increments in isotacticity. The results highlight a combination of MOFs and ATRP that is a promising and universal methodology to prepare various polymers with high molecular weight exhibiting well-defined uniformity in chain length and microstructure as well as the preserved chain-end functionality. Y1 - 2018 U6 - https://doi.org/10.1021/acs.chemmater.8b00546 SN - 0897-4756 SN - 1520-5002 VL - 30 IS - 9 SP - 2983 EP - 2994 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Qin, Qing A1 - Heil, T. A1 - Schmidt, J. A1 - Schmallegger, Max A1 - Gescheidt, Georg A1 - Antonietti, Markus A1 - Oschatz, Martin T1 - Electrochemical Fixation of Nitrogen and Its Coupling with Biomass Valorization with a Strongly Adsorbing and Defect Optimized Boron-Carbon-Nitrogen Catalyst JF - ACS Applied Energy Materials N2 - The electrochemical conversion of low-cost precursors into high-value chemicals using renewably generated electricity is a promising approach to build up an environmentally friendly energy cycle, including a storage element. The large-scale implementation of such process can, however, only be realized by the design of cost-effective electrocatalysts with high efficiency and highest stability. Here, we report the synthesis of N and B codoped porous carbons. The constructed B-N motives combine abundant unpaired electrons and frustrated Lewis pairs (FLPs). They result in desirable performance for electrochemical N-2 reduction reaction (NRR) and electrooxidation of 5-hydroxymethylfurfural (HMF) in the absence of any metal cocatalyst. A maximum Faradaic efficiency of 15.2% with a stable NH3 production rate of 21.3 mu g h(-1) mg(-1) is obtained in NRR. Besides, 2,5-furandicarboxylic acid (FDCA) is first obtained by using non-metalbased electrocatalysts at a conversion of 71% and with yield of 57%. Gas adsorption experiments elucidate the relationship between the structure and the ability of the catalysts to activate the substrate molecules. This work opens up deep insights for the rational design of non-metal-based catalysts for potential electrocatalytic applications and the possible enhancement of their activity by the introduction of FLPs and point defects at grain boundaries. KW - non-metal catalysis KW - porous carbon KW - heteroatoms KW - N-2 reduction KW - HMF oxidation Y1 - 2019 U6 - https://doi.org/10.1021/acsaem.9b01852 SN - 2574-0962 VL - 2 IS - 11 SP - 8359 EP - 8365 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Yan, Runyu A1 - Josef, Elinor A1 - Huang, Haijian A1 - Leus, Karen A1 - Niederberger, Markus A1 - Hofmann, Jan P. A1 - Walczak, Ralf A1 - Antonietti, Markus A1 - Oschatz, Martin T1 - Understanding the charge storage mechanism to achieve high capacity and fast ion storage in sodium-ion capacitor anodes by using electrospun nitrogen-doped carbon fibers JF - Advanced functional materials N2 - Microporous nitrogen-rich carbon fibers (HAT-CNFs) are produced by electrospinning a mixture of hexaazatriphenylene-hexacarbonitrile (HAT-CN) and polyvinylpyrrolidone and subsequent thermal condensation. Bonding motives, electronic structure, content of nitrogen heteroatoms, porosity, and degree of carbon stacking can be controlled by the condensation temperature due to the use of the HAT-CN with predefined nitrogen binding motives. The HAT-CNFs show remarkable reversible capacities (395 mAh g(-1) at 0.1 A g(-1)) and rate capabilities (106 mAh g(-1) at 10 A g(-1)) as an anode material for sodium storage, resulting from the abundant heteroatoms, enhanced electrical conductivity, and rapid charge carrier transport in the nanoporous structure of the 1D fibers. HAT-CNFs also serve as a series of model compounds for the investigation of the contribution of sodium storage by intercalation and reversible binding on nitrogen sites at different rates. There is an increasing contribution of intercalation to the charge storage with increasing condensation temperature which becomes less active at high rates. A hybrid sodium-ion capacitor full cell combining HAT-CNF as the anode and salt-templated porous carbon as the cathode provides remarkable performance in the voltage range of 0.5-4.0 V (95 Wh kg(-1) at 0.19 kW kg(-1) and 18 Wh kg(-1) at 13 kW kg(-1)). KW - carbon fibers KW - nitrogen-doped carbon KW - sodium-ion capacitors KW - sodium storage mechanism Y1 - 2019 U6 - https://doi.org/10.1002/adfm.201902858 SN - 1616-301X SN - 1616-3028 VL - 29 IS - 26 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Lai, Feili A1 - Feng, Jianrui A1 - Hei, Tobias A1 - Wang, Gui-Chang A1 - Adler, Peter A1 - Antonietti, Markus A1 - Oschatz, Martin T1 - Strong metal oxide-support interactions in carbon/hematite nanohybrids activate novel energy storage modes for ionic liquid-based supercapacitors JF - Energy Storage Materials N2 - Strong metal oxide-support interaction is crucial to activate high energy storage modes of carbon-supported hybrid electrodes in ionic liquid-based supercapacitors. Although it is known that conductive supports can influence the electrochemical properties of metal oxides, insights into how metal oxide-support interactions can be exploited to optimize joint energy storage properties are lacking. We report the junction between alpha-Fe2O3 nanosplotches and phosphorus-doped ordered mesoporous carbon (CMK-3-P) with strong covalent anchoring of the metal oxide. The oxide-carbon interaction in CMK-3-P-Fe2O3 is strengthening the junction and charge transfer between Fe2O3 and CMK-3-P. It enhances energy storage by intensifying the interaction between ionic liquid ions and the surface of the electrode. Density functional theory simulations reveal that the strong metal oxide-support interaction increases the adsorption energy of ionic liquid to -4.77 eV as compared to -3.85 eV for a CMK-3Fe(2)O(3) hybrid with weaker binding. In spite of the lower specific surface area and apparently similar energy storage mode, the CMK-3-P-Fe2O3 exhibits superior electrical double-layer capacitor performance with a specific capacitance of 179 F g(-1) at 2 mV s(-1) (0-3.5 V) in comparison to Fe2O3-free CMK-3 and CMK-3-P reference materials. This principle for design of hybrid electrodes can be applicable for future rational design of stable metal oxide-support electrodes for advanced energy storage. KW - Supercapacitor KW - Nanohybrid KW - Iron oxide KW - Ionic liquid KW - Ordering transitions KW - Main text Y1 - 2019 U6 - https://doi.org/10.1016/j.ensm.2019.04.035 SN - 2405-8297 VL - 20 SP - 188 EP - 195 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Walczak, Ralf A1 - Savateev, Aleksandr A1 - Heske, Julian A1 - Tarakina, Nadezda V. A1 - Sahoo, Sudhir A1 - Epping, Jan D. A1 - Kuehne, Thomas D. A1 - Kurpil, Bogdan A1 - Antonietti, Markus A1 - Oschatz, Martin T1 - Controlling the strength of interaction between carbon dioxide and nitrogen-rich carbon materials by molecular design JF - Sustainable energy & fuels N2 - Thermal treatment of hexaazatriphenylene-hexacarbonitrile (HAT-CN) in the temperature range from 500 degrees C to 700 degrees C leads to precise control over the degree of condensation, and thus atomic construction and porosity of the resulting C2N-type materials. Depending on the condensation temperature of HAT-CN, nitrogen contents of more than 30 at% can be reached. In general, these carbons show adsorption properties which are comparable to those known for zeolites but their pore size can be adjusted over a wider range. At condensation temperatures of 525 degrees C and below, the uptake of nitrogen gas remains negligible due to size exclusion, but the internal pores are large and polarizing enough that CO2 can still adsorb on part of the internal surface. This leads to surprisingly high CO2 adsorption capacities and isosteric heat of adsorption of up to 52 kJ mol(-1). Theoretical calculations show that this high binding enthalpy arises from collective stabilization effects from the nitrogen atoms in the C2N layers surrounding the carbon atom in the CO2 molecule and from the electron acceptor properties of the carbon atoms from C2N which are in close proximity to the oxygen atoms in CO2. A true CO2 molecular sieving effect is achieved for the first time in such a metal-free organic material with zeolite-like properties, showing an IAST CO2/N-2 selectivity of up to 121 at 298 K and a N-2/CO2 ratio of 90/10 without notable changes in the CO2 adsorption properities over 80 cycles. Y1 - 2019 U6 - https://doi.org/10.1039/c9se00486f SN - 2398-4902 VL - 3 IS - 10 SP - 2819 EP - 2827 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Youk, Sol A1 - Hofmann, Jan P. A1 - Badamdorj, Bolortuya A1 - Volkel, Antje A1 - Antonietti, Markus A1 - Oschatz, Martin T1 - Controlling pore size and pore functionality in sp(2)-conjugated microporous materials by precursor chemistry and salt templating JF - Journal of materials chemistry : A, Materials for energy and sustainability N2 - The synthesis of sp(2)-conjugated, heteroatom-rich, "carbonaceous" materials from economically feasible raw materials and salt templates is reported. Low cost citrazinic acid (2,6-dihydroxy-4-pyridinecarboxylic acid) and melamine are used as components to form a microporous, amorphous framework, where edges of the covalent frameworks are tightly terminated with nitrogen and oxygen moieties. ZnCl2 as the porogen stabilizes structural microporosity as well as nitrogen and oxygen heteroatoms up to comparably high condensation temperatures of 750 and 950 degrees C. The specific surface area up to 1265 m(2) g(-1) is mainly caused by micropores and typical of heteroatom-rich carbon materials with such structural porosity. The unusually high heteroatom content reveals that the edges and pores of the covalent structures are tightly lined with heteroatoms, while C-C or C-H bonds are expected to have a minor contribution as compared to typical carbon materials without or with minor content of heteroatoms. Adsorption of water vapor and carbon dioxide are exemplarily chosen to illustrate the impact of this heteroatom functionalization under salt-templating conditions on the adsorption properties of the materials. 27.10 mmol g(-1) of H2O uptake (at p/p(0) = 0.9) can be achieved, which also proves the very hydrophilic character of the pore walls, while the maximum CO2 uptake (at 273 K) is 5.3 mmol g(-1). At the same time the CO2/N-2 adsorption selectivity at 273 K can reach values of up to 60. All these values are beyond those of ordinary high surface area carbons, also differ from those of N-doped carbons, and are much closer to those of organized framework species, such as C2N. Y1 - 2020 U6 - https://doi.org/10.1039/d0ta05856d SN - 2050-7488 SN - 2050-7496 VL - 8 IS - 41 SP - 21680 EP - 21689 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Al-Naji, Majd A1 - Schlaad, Helmut A1 - Antonietti, Markus T1 - New (and old) monomers from biorefineries to make polymer chemistry more sustainable JF - Macromolecular rapid communications N2 - This opinion article describes recent approaches to use the "biorefinery" concept to lower the carbon footprint of typical mass polymers, by replacing parts of the fossil monomers with similar or even the same monomer made from regrowing dendritic biomass. Herein, the new and green catalytic synthetic routes are for lactic acid (LA), isosorbide (IS), 2,5-furandicarboxylic acid (FDCA), and p-xylene (pXL). Furthermore, the synthesis of two unconventional lignocellulosic biomass derivable monomers, i.e., alpha-methylene-gamma-valerolactone (MeGVL) and levoglucosenol (LG), are presented. All those have the potential to enter in a cost-effective way, also the mass market and thereby recover lost areas for polymer materials. The differences of catalytic unit operations of the biorefinery are also discussed and the challenges that must be addressed along the synthesis path of each monomers. KW - biodegradable polymers KW - biorefineries KW - carbohydrate‐ based KW - monomers KW - green polymers KW - lignocellulosic biomass Y1 - 2020 U6 - https://doi.org/10.1002/marc.202000485 SN - 1022-1336 SN - 1521-3927 VL - 42 IS - 3 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Chen, Lu A1 - Yan, Runyu A1 - Oschatz, Martin A1 - Jiang, Lei A1 - Antonietti, Markus A1 - Xiao, Kai T1 - Ultrathin 2D graphitic carbon nitride on metal films BT - underpotential sodium deposition in adlayers for sodium-ion batteries JF - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition N2 - Efficient and low-cost anode materials for the sodium-ion battery are highly desired to enable more economic energy storage. Effects on an ultrathin carbon nitride film deposited on a copper metal electrode are presented. The combination of effects show an unusually high capacity to store sodium metal. The g-C3N4 film is as thin as 10 nm and can be fabricated by an efficient, facile, and general chemical-vapor deposition method. A high reversible capacity of formally up to 51 Ah g(-1) indicates that the Na is not only stored in the carbon nitride as such, but that carbon nitride activates also the metal for reversible Na-deposition, while forming at the same time an solid electrolyte interface layer avoiding direct contact of the metallic phase with the liquid electrolyte. KW - 2D films KW - carbon nitride KW - chemical vapor deposition KW - sodium-ion KW - batteries KW - underpotential deposition Y1 - 2020 U6 - https://doi.org/10.1002/anie.202000314 SN - 1433-7851 SN - 1521-3773 VL - 59 IS - 23 SP - 9067 EP - 9073 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Ilic, Ivan K. A1 - Tsouka, Alexandra A1 - Perovic, Milena A1 - Hwang, Jinyeon A1 - Heil, Tobias A1 - Löffler, Felix A1 - Oschatz, Martin A1 - Antonietti, Markus A1 - Liedel, Clemens T1 - Sustainable cathodes for Lithium-ion energy storage devices based on tannic acid-toward ecofriendly energy storage JF - Advanced sustainable systems N2 - The use of organic materials with reversible redox activity holds enormous potential for next-generation Li-ion energy storage devices. Yet, most candidates are not truly sustainable, i.e., not derived from renewable feedstock or made in benign reactions. Here an attempt is reported to resolve this issue by synthesizing an organic cathode material from tannic acid and microporous carbon derived from biomass. All constituents, including the redox-active material and conductive carbon additive, are made from renewable resources. Using a simple, sustainable fabrication method, a hybrid material is formed. The low cost and ecofriendly material shows outstanding performance with a capacity of 108 mAh g(-1) at 0.1 A g(-1) and low capacity fading, retaining approximately 80% of the maximum capacity after 90 cycles. With approximately 3.4 V versus Li+/Li, the cells also feature one of the highest reversible redox potentials reported for biomolecular cathodes. Finally, the quinone-catecholate redox mechanism responsible for the high capacity of tannic acid is confirmed by electrochemical characterization of a model compound similar to tannic acid but without catecholic groups. KW - biomass KW - electrochemistry KW - energy storage KW - redox chemistry KW - sustainability KW - tannic acid Y1 - 2020 U6 - https://doi.org/10.1002/adsu.202000206 SN - 2366-7486 VL - 5 IS - 1 PB - Wiley-VCH CY - Weinheim ER -