FG Technische Chemie

47 Items

Recent Submissions
Real-time imaging of activation and degradation of carbon supported octahedral Pt–Ni alloy fuel cell catalysts at the nanoscale using in situ electrochemical liquid cell STEM

Beermann, Vera ; Holtz, Megan E. ; Padgett, Elliot ; de Araujo, Jorge Ferreira ; Muller, David A. ; Strasser, Peter (2019-05-20)

Octahedrally shaped Pt–Ni alloy nanoparticles on carbon supports have demonstrated unprecedented electrocatalytic activity for the oxygen reduction reaction (ORR), sparking interest as catalysts for low-temperature fuel cell cathodes. However, deterioration of the octahedral shape that gives the catalyst its superior activity currently prohibits the use of shaped catalysts in fuel cell devices,...

Precious metal-free bifunctional catalysts for reversible seawater electrolyzers

Dresp, Sören (2019)

Regenerative hydrogen, which is produced by renewable electricity used in water electrolyzers, is considered as ideal energy carrier of the future. The selective splitting of seawater into oxygen and hydrogen seem to be a promising alternative compared to established water electrolysis technologies, which typically use highly purified water and electrolytes only. In addition, the back transform...

Pulsed laser deposition of efficient ternary metal oxide photoelectrodes

Kölbach, Moritz (2019)

Climate change, mainly driven by the combustion of fossil fuels releasing the greenhouse gas CO2, is a major threat to humanity and the ecosystems on our planet. To limit global warming, a transition towards a sustainable energy infrastructure based on renewable energies is essential. The storage of solar energy in the form of chemical bonds, in so-called solar fuels, is thereby believed to be ...

In situ studies of Pt nanoparticles on different supports for corrosion stable PEM fuel cell cathodes

Schmies, Henrike (2019)

Wasserstoffbrennstoffzellen bieten als elektrochemische Energiewandler die Möglichkeit, Wasserstoff aus erneuerbaren Resourcen als saubere und emissionsarme Energiequelle für elektrische Verbraucher, wie Elektromotoren, zu nutzen. Um eine konkurrenzfähige Alternative zu heutigen Verbrennungsmotoren in der Automobilindustrie darstellen zu können, müssen aber noch verschiedenste Hindernisse überw...

A new inductive-annealing dual electrochemical cell for crystal alloy and thin-film electrode voltammetry

Özer, Ebru (2019)

Proton exchange membrane (PEM) electrolyzers are considered as the most promising candidates for the supply of high purity hydrogen through water electrolysis. As a non polluting technology these electrolyzers enable to store surplus electricity of intermittent renewable power sources. In the highly acidic corrosive media of PEM electrolyzers, noble metal materials and their oxides represent th...

Studies on shape defined Pt-alloy based nanoparticles for the electrochemical reduction of oxygen

Beermann, Vera (2018)

Fuel cells represent an almost ideal technology to provide electricity from sustainable energies. However, to date expensive platinum catalysts are used which do not provide sufficient performances at the cathode side where the oxygen reduction reaction (ORR) takes place. A cost-efficient and active alternative is represented by the group of Pt-Ni alloys. Octahedral shaped Pt-Ni alloy nanoparti...

Palladium-catalyzed hydroxycarbonylation of 1-dodecene in microemulsion systems: does reaction performance care about phase behavior?

Schmidt, Marcel ; Urban, Carolina ; Schmidt, Svenja ; Schomäcker, Reinhard (2018-10-17)

Catalysis, particularly metal-catalyzed reactions in microemulsion systems, offers a sustainable approach for organic reactions in water. However, it is still a challenging task because of the complex role of the nonionic surfactant in such a system and the interaction of the phase behavior and reaction performance. To get a profound knowledge of this role and interaction, a systematic study of...

Comparison of alkane activation over supported and bulk transition metal oxide catalysts and transition metal free carbon nano structures

Kube, Pierre (2018)

Vanadium-based and transition metal-free catalysts have been extensively studied during the last decades in the partial oxidation of ethane and propane due to the high activity and good selectivity. The selectivity to the desired olefin is, however, still too low for industrial application. Improvements require at first an in-depth understanding of the entire reaction network and the relation o...

Grazing incidence X-ray diffraction

Scherzer, Michael (2018)

The interest to study iridium electrocatalysts originates from their use in PEM electrolyzers, which are used to produce hydrogen from water splitting. The need to overcome the exploitation of fossil fuels and to promote the use of sustainable resources makes this a promising alternative. Usage of expensive and rare iridium additionally pushes research to find cost efficient alternatives, proba...

Surface plasmon resonance based sensor for the detection of glycopeptide antibiotics in milk using rationally designed nanoMIPs

Altintas, Zeynep (2017-07-25)

Glycopeptide antibiotics are known as the last resort for the treatment of serious infections caused by Gram-positive bacteria. The use of milk products contaminated with these antibiotic residues leads to allergic reactions and sensitivity in human. Also, long-term consumption of milk products containing low levels of these antibiotics may cause the relevant bacteria to build up resistance to ...

Property-performance correlations in the oxidative coupling of methane

Wang, Huan (2018)

The oxidative coupling of methane is a “dream reaction” in heterogeneous catalysis to achieve direct conversion for natural gas towards value-added and easily transportable C2 products with high economic relevance. Although extensive academic papers and patents have been reported over the last three decades, no economically viable industrial-scale application is yet achieved because of the limi...

Rhodium-catalysed hydroformylation of long-chain alkenes in aqueous multiphase systems: Kinetic studies and systematic process development

Pogrzeba, Tobias (2018)

In the course of the development of new sustainable industrial chemical processes the exploitation of switchable solvent systems is increasingly investigated in various fields. The application of highly efficient catalysts and safer solvents is mandatory to make a step towards a greener chemistry, as well as to find innovative ways to reduce waste from chemical reactions. Consequently, the use ...

High throughput modules for performance and mechanism assessment of flame retardants in polymeric materials

Rabe, Sebastian (2017)

Due to the ever-increasing number of additives, adjuvants, synergists, and fillers, together with variations in concentration, particle size distribution and other modifications, methods for accelerated assessment of flame retarded polymeric materials are strongly needed. This work presents two novel approaches to assess the rapid screening of flame retardants in polymeric materials. Furthermor...

Record activity and stability of dealloyed bimetallic catalysts for proton exchange membrane fuel cells

Han, Binghong ; Carlton, Christopher E. ; Kongkanand, Anusorn ; Kukreja, Ratandeep S. ; Theobald, Brian R. ; Gan, Lin ; O'Malley, Rachel ; Strasser, Peter ; Wagner, Frederick T. ; Shao-Horn, Yang (2015)

We demonstrate the unprecedented proton exchange membrane fuel cell (PEMFC) performance durability of a family of dealloyed Pt-Ni nanoparticle catalysts for the oxygen reduction reaction (ORR), exceeding scientific and technological state-of-art activity and stability targets. We provide atomic-scale insight into key factors controlling the stability of the cathode catalyst by studying the infl...

Reliable palladium nanoparticle syntheses in aqueous solution: the importance of understanding precursor chemistry and growth mechanism

Kettemann, Frieder ; Wuithschick, Maria ; Caputo, Gianvito ; Krähnert, Ralph ; Pinna, Nicola ; Rademann, Klaus ; Polte, Jörg (2015)

Reliable protocols for the synthesis of palladium nanoparticles (Pd-NPs) in aqueous solution are rarely found and the corresponding growth mechanisms often remain unknown. Furthermore, syntheses of Pd-NPs always demand the use of stabilizing agents which are often unfavorable for catalytic applications. In this contribution, the importance of the palladium precursor chemistry as a prerequisite ...

From molecular copper complexes to composite electrocatalytic materials for selective reduction of CO2 to formic acid

Tran Ngoc Huan ; Andreiadis, Eugen S. ; Heidkamp, Jonathan ; Simon, Philippe ; Derat, Etienne ; Cobo, Saioa ; Royal, Guy ; Bergmann, Arno ; Strasser, Peter ; Dau, Holger ; Artero, Vincent ; Fontecave, Marc (2015)

The development of new energy storage technologies is central to solving the challenges facing the widespread use of renewable energies. An option is the reduction of carbon dioxide (CO2) into carbon-based products which can be achieved within an electrochemical cell. Future developments of such processes depend on the availability of cheap and selective catalysts at the electrode. Here we show...

Oxide-supported Ir nanodendrites with high activity and durability for the oxygen evolution reaction in acid PEM water electrolyzers

Oh, Hyung-Suk ; Nong, Hong Nhan ; Reier, Tobias ; Gliech, Manuel ; Strasser, Peter (2015)

Reducing the noble-metal catalyst content of acid Polymer Electrolyte Membrane (PEM) water electrolyzers without compromising catalytic activity and stability is a goal of fundamental scientific interest and substantial technical importance for cost-effective hydrogen-based energy storage. This study presents nanostructured iridium nanodendrites (Ir-ND) supported on antimony doped tin oxide (AT...

Time-resolved in situ studies on the formation mechanism of iron oxide nanoparticles using combined fast-XANES and SAXS

Kabelitz, Anke ; Guilherme, Ana ; Joester, Maike ; Reinholz, Uwe ; Radtke, Martin ; Bienert, Ralf ; Schulz, Katrin ; Schmack, Roman ; Krähnert, Ralph ; Emmerling, Franziska (2015)

The reaction of iron chlorides with an alkaline reagent is one of the most prominent methods for the synthesis of iron oxide nanoparticles. We studied the particle formation mechanism using triethanolamine as reactant and stabilizing agent. In situ fast-X-ray absorption near edge spectroscopy and small-angle X-ray scattering provide information on the oxidation state and the structural informat...

Hydrophilic non-precious metal nitrogen-doped carbon electrocatalysts for enhanced efficiency in oxygen reduction reaction

Hao, Guang-Ping ; Sahraie, Nastaran Ranjbar ; Zhang, Qiang ; Krause, Simon ; Oschatz, Martin ; Bachmatiuk, Alicja ; Strasser, Peter ; Kaskel, Stefan (2015)

Exploring the role of surface hydrophilicity of non-precious metal N-doped carbon electrocatalysts in electrocatalysis is challenging. Herein we discover an ultra-hydrophilic non-precious carbon electrocatalyst, showing enhanced catalysis efficiency on both gravimetric and areal basis for oxygen reduction reaction due to a high dispersion of active centres.

An efficient bifunctional two-component catalyst for oxygen reduction and oxygen evolution in reversible fuel cells, electrolyzers and rechargeable air electrodes

Dresp, Sören ; Luo, Fang ; Schmack, Roman ; Kühl, Stefanie ; Gliech, Manuel ; Strasser, Peter (2016)

We report on a non-precious, two-phase bifunctional oxygen reduction and evolution (ORR and OER) electrocatalyst with previously unachieved combined roundtrip catalytic reactivity and stability for use in oxygen electrodes of unitized reversible fuel cell/electrolyzers or rechargeable metal-air batteries. The combined OER and ORR overpotential, total, at 10 mA cm(-2) was a record low value of 0...