FG Funktionsmaterialien

30 Items

Recent Submissions
Cobalt‐Exchanged Poly(Heptazine Imides) as Transition Metal–Nx Electrocatalysts for the Oxygen Evolution Reaction

Ye, Meng‐Yang ; Li, Shuang ; Zhao, Xiaojia ; Tarakina, Nadezda V. ; Teutloff, Christian ; Chow, Wing Ying ; Bittl, Robert ; Thomas, Arne (2020-01-27)

Poly(heptazine imides) hosting cobalt ions as countercations are presented as promising electrocatalysts for the oxygen evolution reaction (OER). A facile mixed‐salt melt‐assisted condensation is developed to prepare such cobalt poly(heptazine imides) (PHI‐Co). The Co ions can be introduced in well‐controlled amounts using this method, and are shown to be atomically dispersed within the imide‐l...

Colloid-based heterogeneous catalysts with tunable size and surface properties

Sagaltchik, Anton (2020)

Improvements in catalyst’s performance for technical processes stagnated over the last decades. The need for new approaches towards better performing catalysts is apparent. In this thesis, colloidal synthesis methods are examined for different heterogeneously catalyzed reactions. In chapter 2, synthesis of silver colloids with narrow particle size distributions for a particle size distribution...

Pd nanoparticles confined in mesoporous N-doped carbon silica supports: a synergistic effect between catalyst and support

Oliveira, Rafael L. ; Kerstien, Julius ; Schomäcker, Reinhard ; Thomas, Arne (2020-01-21)

Palladium nanoparticles of similar size were deposited on different supports, layers of carbon materials (with and without nitrogen doping) on the surface of a MCF (mesocellular foam) silica. For the generation of the N-doped carbon coatings, three different N sources were used to also investigate a possible influence of the N-doped carbon precursor and thus the structure of the N-doped carbons...

Vinylene-Linked Covalent Organic Frameworks by Base-Catalyzed Aldol Condensation

Acharjya, Amitava ; Pachfule, Pradip ; Roeser, Jérôme ; Schmitt, Franz-Josef ; Thomas, Arne (2019-09-09)

Two 2D covalent organic frameworks (COFs) linked by vinylene (−CH=CH−) groups (V‐COF‐1 and V‐COF‐2) are synthesized by exploiting the electron deficient nature of the aromatic s‐triazine unit of C3‐symmetric 2,4,6‐trimethyl‐s‐triazine (TMT). The acidic terminal methyl hydrogens of TMT can easily be abstracted by a base, resulting in a stabilized carbanion, which further undergoes aldol condensa...

Sythesis of functional nanoporous materials for electrocatalytic applications

Zhao, Xiaojia (2019)

Recently, the International Energy Agency has reported that the global energy demand is growing at the fastest pace this decade, while fossil fuels are leading the charge. The outcome of this is a higher carbon dioxide emission and environmental pollution, which can only be averted by developing all clean energy solutions and improving their efficiency. The development of electrocatalysis for r...

Optimisation of Surface-Initiated Photoiniferter-Mediated Polymerisation under Confinement, and the Formation of Block Copolymers in Mesoporous Films

Tom, Jessica ; Brilmayer, Robert ; Schmidt, Johannes ; Andrieu-Brunsen, Annette (2017-10-23)

Nature as the ultimate inspiration can direct, gate, and selectively transport species across channels to fulfil a specific targeted function. Harnessing such precision over local structure and functionality at the nanoscale is expected to lead to indispensable developments in synthetic channels for application in catalysis, filtration and sensing, and in drug delivery. By combining mesoporous ...

Relations between Structure, Activity and Stability in C3N4 Based Photocatalysts Used for Solar Hydrogen Production

Sivasankaran, Ramesh P. ; Rockstroh, Nils ; Hollmann, Dirk ; Kreyenschulte, Carsten R. ; Agostini, Giovanni ; Lund, Henrik ; Acharjya, Amitava ; Rabeah, Jabor ; Bentrup, Ursula ; Junge, Henrik ; Thomas, Arne ; Brückner, Angelika (2018-01-29)

Solar hydrogen production from water could be a sustainable and environmentally friendly alternative to fossil energy carriers, yet so far photocatalysts active and stable enough for large-scale applications are not available, calling for advanced research efforts. In this work, H2 evolution rates of up to 1968 and 5188 μmol h−1 g−1 were obtained from aqueous solutions of triethanolamine (TEOA)...

Structure–Thermodynamic‐Property Relationships in Cyanovinyl‐Based Microporous Polymer Networks for the Future Design of Advanced Carbon Capture Materials

Yassin, Ali ; Trunk, Matthias Georg ; Czerny, Frank ; Fayon, Pierre ; Trewin, Abbie ; Schmidt, Johannes ; Thomas, Arne (2017)

Nitrogen‐rich solid absorbents, which have been immensely tested for carbon dioxide capture, seem until this date to be without decisive molecular engineering or design rules. Here, a family of cyanovinylene‐based microporous polymers synthesized under metal‐catalyzed conditions is reported as a promising candidate for advanced carbon capture materials. These networks reveal that isosteric heat...

Room-Temperature Activation of Hydrogen by Semi-immobilized Frustrated Lewis Pairs in Microporous Polymer Networks

Trunk, Matthias Georg ; Teichert, Johannes F. ; Thomas, Arne (2017)

Porous polymer networks based on sterically encumbered triphenylphosphine motifs, mimicking the basic sites employed in frustrated Lewis pair (FLP) chemistry, were synthesized via Yamamoto polymerization and their interactions with the strong Lewis acid B(C6F5)3 probed. The combinations yield semi-immobilized FLPs, which are able to cleave dihydrogen heterolytically at ambient temperature and l...

Nanostructured porous carbon synthesized from metal-organic precursors as efficient electrochemical catalysts

Li, Shuang (2019)

The development of electrocatalysts for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) is of crucial importance to address the global demand for sustainable energy conversion devices with high efficiency, such as fuel cells and metal–air batteries, and the production of hydrogen by electrolysis of water. Nanostructured carbons are pro...

Copper‐Free Sonogashira Coupling for High‐Surface‐Area Conjugated Microporous Poly(aryleneethynylene) Networks

Trunk, Matthias Georg ; Herrmann, Anna ; Bildirir, Hakan ; Yassin, Ali ; Schmidt, Johannes ; Thomas, Arne (2016)

A modified one‐pot Sonogashira cross‐coupling reaction based on a copper‐free methodology has been applied for the synthesis of conjugated microporous poly(aryleneethynylene) networks (CMPs) from readily available iodoarylenes and 1,3,5‐triethynylbenzene. The polymerization reactions were carried out by using equimolar amounts of halogen and terminal alkyne moieties with extremely small loading...

Frustrated Lewis pairs embedded into microporous polymer networks

Trunk, Matthias Georg (2018)

Aufgrund ihrer vielseitigen potentiellen Anwendungsmöglichkeiten in Gasspeicherung und –trennung, Sensorik und Katalyse haben mikroporöse organische Materialien innerhalb der letzten 20 Jahre eine rasante Entwicklung erfahren. Neben geordneten Materialien wie metall-organischen Gerüstmaterialien (MOFs) und kovalent organischen Gerüstmaterialien (COFs) haben sich mikroporöse Polymernetzwerke (MP...

Bioinspired solid catalysts for the hydroxylation of methane

Le, Ha Vu (2018)

Abundant and cheap resources including natural gas, methane hydrates, and biogas, whose major component is methane, have been considered as promising alternatives to decline the dependence of chemical and energy industries on crude oil. However, there is currently an underutilization of these resources, especially due to the costly transportation and storage, and high chemical inertness of meth...

Multinary metal oxides for solar water splitting

Wang, Fuxian (2017)

The world has experienced an exponential increase in the demand for energy primarily coming from the consumption of fossil fuels, which is accompanied by the inevitable emission of carbon dioxide, causing global warming. Developing renewable and carbon-free sources is essential to reduce carbon dioxide emission and mitigate global warming. Among the renewable energy sources, solar energy has th...

Microporous polymer network films covalently bound to gold electrodes

Becker, Daniel ; Heidary, Nina ; Horch, Marius ; Gernert, Ulrich ; Zebger, Ingo ; Schmidt, Johannes ; Fischer, Anna ; Thomas, Arne (2015)

Covalent attachment of a microporous polymer network (MPN) on a gold surface is presented. A functional bromophenyl-based self-assembled monolayer (SAM) formed on the gold surface acts as co-monomer in the polymerisation of the MPN yielding homogeneous and robust coatings. Covalent binding of the films to the electrode is confirmed by SEIRAS measurements.

Synthesis of efficient photocatalysts for water oxidation and dye degradation reactions using CoCl2 eutectics

Fettkenhauer, Christian ; Wang, Xinchen ; Kailasam, Kamalakannan ; Antonietti, Markus ; Dontsova, Dariya (2015)

A simple one-step procedure for the preparation of cobalt oxide-carbon nitride composites by carrying out the thermal condensation reaction of carbon nitride precursors in cobalt(II) chloride-containing salt melts is developed. This method enables us to control the structure of the polymer constituent by the proper selection of the second eutectic component. In this respect, alkali metal chlori...

Conversion of amorphous polymer networks to covalent organic frameworks under ionothermal conditions: a facile synthesis route for covalent triazine frameworks

Kücken, Sophie ; Schmidt, Johannes ; Zhi, Linjie ; Thomas, Arne (2015)

The conversion of an amorphous, non-porous polymer network into an ordered, microporous covalent organic framework under ionothermal conditions is presented. The amorphous polymer network is prepared by trimerization of carbonitrile monomers using strong Broensted acids. In a second step the polymer network is converted into a porous covalent triazine framework (CTF) under ionothermal condition...

Nickel as a co-catalyst for photocatalytic hydrogen evolution on graphitic-carbon nitride (sg-CN): what is the nature of the active species?

Indra, Arindam ; Menezes, Prashanth W. ; Kailasam, Kamalakannan ; Hollmann, Dirk ; Schröder, Marc ; Thomas, Arne ; Brückner, Angelika ; Drieß, Matthias (2016)

The nature of a nickel-based co-catalyst deposited on a sol-gel prepared porous graphitic-carbon nitride (sg-CN), for photocatalytic H-2 production from water, has been investigated. The formation of the active catalytic species, charge separation and recombination of the photogenerated electrons and holes during photochemical H-2 evolution has been determined for the first time using in situ E...

Comparison of conventional and super-glassy polymers

Konnertz, Nora Magdalena (2017)

In the field of gas separation, polymeric membranes are favorable materials. Polymers are inexpensive compared to ceramics and metals, offer a good processability, and possess the ability to operate at large scale. The most important fact about polymeric membranes is their good selectivity. Nevertheless, most of the polymeric membranes show a strong tendency to physical aging and plasticization...

Synthesis, characterization and catalytic testing of metal tungstates as catalysts for activation of lower alkanes

Li, Xuan (2017)

The electronic and structural properties of vanadium-containing phases govern the formation of isolated active sites at the surface of these catalysts for selective alkane oxidation. This concept is not restricted to vanadium oxide. The deliberate use of hydrothermal techniques can turn the typical combustion catalyst manganese oxide into a selective catalyst for oxidative dehydrogenation of pr...