FG Technische Chemie

81 Items

Recent Submissions
In-situ structure and catalytic mechanism of NiFe and CoFe layered double hydroxides during oxygen evolution

Dionigi, Fabio ; Zeng, Zhenhua ; Sinev, Ilya ; Merzdorf, Thomas ; Deshpande, Siddharth ; Lopez, Miguel Bernal ; Kunze, Sebastian ; Zegkinoglou, Ioannis ; Sarodnik, Hannes ; Dingxin Fan, Dingxin Fan ; Bermann, Arno ; Drnec, Jakub ; Araujo, Jorge Ferreira de ; Gliech, Manuel ; Teschner, Detre ; Zhu, Jing ; Li, Wei-Xue ; Greeley, Jeffrey ; Cuenya, Beatriz Roldan ; Strasser, Peter (2020-05-20)

NiFe and CoFe (MFe) layered double hydroxides (LDHs) are among the most active electrocatalysts for the alkaline oxygen evolution reaction (OER). Herein, we combine electrochemical measurements, operando X-ray scattering and absorption spectroscopy, and density functional theory (DFT) calculations to elucidate the catalytically active phase, reaction center and the OER mechanism. We provide the...

Electrocatalytic CO2 reduction on CuOx nanocubes: Tracking the evolution of chemical state, geometric structure, and catalytic selectivity using operando spectroscopy

Möller, Tim ; Scholten, Fabian ; Thanh, Trung Ngo ; Sinev, Ilya ; Timoshenko, Janis ; Wang, Xingli ; Jovanov, Zarko ; Gliech, Manuel ; Cuenya, Beatriz Roldan ; Varela, Ana Sofia ; Strasser, Peter (2020-07-06)

The direct electrochemical conversion of carbon dioxide (CO2) into multi-carbon (C2+) products still faces fundamental and technological challenges. While facet-controlled and oxide-derived Cu materials have been touted as promising catalysts, their stability has remained problematic and poorly understood. Herein we uncover changes in the chemical and morphological state of supported and unsupp...

Morphology and mechanism of highly selective Cu(II) oxide nanosheet catalysts for carbon dioxide electroreduction

Wang, Xingli ; Klingan, Katharina ; Klingenhof, Malte ; Möller, Tim ; Araújo, Jorge Ferreira de ; Martens, Isaac ; Bagger, Alexander ; Jiang, Shan ; Rossmeisl, Jan ; Dau, Holger ; Strasser, Peter (2021-02-04)

Cu oxides catalyze the electrochemical carbon dioxide reduction reaction (CO2RR) to hydrocarbons and oxygenates with favorable selectivity. Among them, the shape-controlled Cu oxide cubes have been most widely studied. In contrast, we report on novel 2-dimensional (2D) Cu(II) oxide nanosheet (CuO NS) catalysts with high C2+ products, selectivities (> 400 mA cm−2) in gas diffusion electrodes (GD...

Bridging experiment and theory: enhancing the electrical conductivities of soft-templated niobium-doped mesoporous titania films

Frisch, Marvin ; Laun, Joachim ; Marquardt, Julien ; Arinchtein, Aleks ; Bauerfeind, Katharina ; Bernsmeier, Denis ; Bernicke, Michael ; Bredow, Thomas ; Kraehnert, Ralph (2021-02-03)

Theoretical calculations suggest a strong dependence of electrical conductivity and doping concentration in transition-metal doped titania. Herein, we present a combined theoretical and experimental approach for the prediction of relative phase stability and electrical conductivity in niobium-doped titania as model system. Our method paves the way towards the development of materials with impro...

Potential-driven surface phase transitions on iridium (hydr-)oxides and their relation to electrolytic water splitting

Falling, Lorenz (2021)

The burning of fossil fuels and the resultant release of CO2 into the atmosphere is the only tenable explanation for the rapid progression of climate change in recent decades. A sustainable energy economy is urgently needed to reduce the use of fossil fuels significantly. Hydrogen has been proposed to play a strategic role in this new energy economy and PEM electrolyzers are a promising way to ...

Transition metal-doped calcium oxide as model catalyst for the oxygen activation in the oxidative coupling of methane (OCM) reaction

Thum, Lukas (2020)

To find alternative feedstocks for the chemical industry, the oxidative coupling of methane (OCM) reaction was developed in the 1980s, allowing the production of ethylene from methane. Though, being the topic of many investigations in the last 40 years, the success so far is limited and a yield of 30% has yet to be surpassed. One major issue of the reaction is the activation of methane. With a ...

Iron and Manganese Containing Multi‐Walled Carbon Nanotubes as Electrocatalysts for the Oxygen Evolution Reaction ‐ Unravelling Influences on Activity and Stability

Broicher, Cornelia ; Zeng, Feng ; Pfänder, Norbert ; Frisch, Marvin ; Bisswanger, Timo ; Radnik, Jörg ; Stockmann, Jörg Manfred ; Palkovits, Stefan ; Beine, Anna Katharina ; Palkovits, Regina (2020-09-24)

Hydrogen economy is a central aspect of future energy supply, as hydrogen can be used as energy storage and fuel. In order to make water electrolysis efficient, the limiting oxygen evolution reaction (OER) needs to be optimized. Therefore, C‐based composite materials containing earth‐abundant Fe and Mn were synthesized, characterized and tested in the OER. For pyrolysis temperatures above 700 °...

Electrocatalytic CO2 Reduction on CuOx Nanocubes: Tracking the Evolution of Chemical State, Geometric Structure, and Catalytic Selectivity using Operando Spectroscopy

Möller, Tim ; Scholten, Fabian ; Thanh, Trung Ngo ; Sinev, Ilya ; Timoshenko, Janis ; Wang, Xingli ; Jovanov, Zarko ; Gliech, Manuel ; Roldan Cuenya, Beatriz ; Varela, Ana Sofia ; Strasser, Peter (2020-08-13)

The direct electrochemical conversion of carbon dioxide (CO2) into multi‐carbon (C2+) products still faces fundamental and technological challenges. While facet‐controlled and oxide‐derived Cu materials have been touted as promising catalysts, their stability has remained problematic and poorly understood. Herein we uncover changes in the chemical and morphological state of supported and unsupp...

Solute Incorporation at Oxide–Oxide Interfaces Explains How Ternary Mixed‐Metal Oxide Nanocrystals Support Element‐Specific Anisotropic Growth

Gliech, Manuel ; Görlin, Mikaela ; Gocyla, Martin ; Klingenhof, Malte ; Bergmann, Arno ; Selve, Sören ; Spöri, Camillo ; Heggen, Marc ; Dunin‐Borkowski, Rafal E. ; Suntivich, Jin ; Strasser, Peter (2020-01-20)

Fundamental understanding of anisotropic growth in oxide nanocrystals is crucial to establish new synthesis strategies and to tailor the nanoscale electronic, magnetic, optical, and electrocatalytic properties of these particles. While several growth investigations of metal alloy nanoparticles have been reported, mechanistic studies on the growth of ternary oxide materials are still missing. Th...

Anisotropy of Pt nanoparticles on carbon- and oxide-support and their structural response to electrochemical oxidation probed by in situ techniques

Schmies, Henrike ; Bergmann, Arno ; Hornberger, Elisabeth ; Drnec, Jakub ; Wang, Guanxiong ; Dionigi, Fabio ; Kühl, Stefanie ; Sandbeck, Daniel J. S. ; Mayrhofer, Karl J. J. ; Ramani, Vijay ; Cherevko, Serhiy ; Strasser, Peter (2020-09-08)

Identifying the structural response of nanoparticle–support ensembles to the reaction conditions is essential to determine their structure in the catalytically active state as well as to unravel the possible degradation pathways. In this work, we investigate the (electronic) structure of carbon- and oxide-supported Pt nanoparticles during electrochemical oxidation by in situ X-ray diffraction, ...

Graphene Quantum Dots as Flourishing Nanomaterials for Bio-Imaging, Therapy Development, and Micro-Supercapacitors

Kortel, Merve ; Mansuriya, Bhargav D. ; Vargas Santana, Nicole ; Altintas, Zeynep (2020-09-18)

Graphene quantum dots (GQDs) are considerably a new member of the carbon family and shine amongst other members, thanks to their superior electrochemical, optical, and structural properties as well as biocompatibility features that enable us to engage them in various bioengineering purposes. Especially, the quantum confinement and edge effects are giving GQDs their tremendous character, while t...

Current challenges related to the deployment of shape-controlled Pt alloy oxygen reduction reaction nanocatalysts into low Pt-loaded cathode layers of proton exchange membrane fuel cells

Pan, Lujin ; Ott, Sebastian ; Dionigi, Fabio ; Strasser, Peter (2019-10-25)

The reduction of the amount of platinum used in proton exchange membrane fuel cell cathodes at constant power density helps lower the cell stack cost of fuel cell electric vehicles. Recent screening studies using the thin film rotating disk electrode technique have identified an ever-growing number of Pt-based nanocatalysts with oxygen reduction reaction Ptmass activities that allow for a subst...

A comparative perspective of electrochemical and photochemical approaches for catalytic H2O2 production

Sun, Yanyan ; Han, Lei ; Strasser, Peter (2020-08-06)

Hydrogen peroxide (H2O2) has a wide range of important applications in various fields including chemical industry, environmental remediation, and sustainable energy conversion/storage. Nevertheless, the stark disconnect between today's huge market demand and the historical unsustainability of the currently-used industrial anthraquinone-based production process is promoting extensive research on...

Establishing reactivity descriptors for platinum group metal (PGM)-free Fe–N–C catalysts for PEM fuel cells

Primbs, Mathias ; Sun, Yanyan ; Roy, Aaron ; Malko, Daniel ; Mehmood, Asad ; Sougrati, Moulay-Tahar ; Blanchard, Pierre-Yves ; Granozzi, Gaetano ; Kosmala, Tomasz ; Daniel, Giorgia ; Atanassov, Plamen ; Sharman, Jonathan ; Durante, Christian ; Kucernak, Anthony ; Jones, Deborah ; Jaouen, Frédéric ; Strasser, Peter (2020-06-24)

We report a comprehensive analysis of the catalytic oxygen reduction reaction (ORR) reactivity of four of today's most active benchmark platinum group metal-free (PGM-free) iron/nitrogen doped carbon electrocatalysts (Fe–N–Cs). Our analysis reaches far beyond previous such attempts in linking kinetic performance metrics, such as electrocatalytic mass-based and surface area-based catalytic activ...

Efficient direct seawater electrolysers using selective alkaline NiFe-LDH as OER catalyst in asymmetric electrolyte feeds

Dresp, Sören ; Thanh, Trung Ngo ; Klingenhof, Malte ; Brückner, Sven ; Hauke, Philipp ; Strasser, Peter (2020-05-20)

Direct seawater electrolysis faces fundamental catalytic and process engineering challenges. Here we demonstrate a promising seawater electrolyser configuration using asymmetric electrolyte feeds. We further investigated the faradaic O2 efficiency of NiFe-LDH in alkalinized Cl−-containing electrolytes in comparison to commercial IrOx-based catalysts. Other than IrOx, NiFe-LDH prevents the oxida...

Synthesis and characterization of Cu-based multinary metal oxides for photoelectrochemical water splitting

Song, Angang (2020)

In the future, the storage of solar energy in the form of chemical bonds is expected to be a key method for solar energy conversion. Photoelectrochemical (PEC) water splitting is one of the most important approaches to convert solar energy into chemical bonds via production of hydrogen. However, there are numerous scientific challenges in developing this PEC water splitting, including the ident...

Copper-based nanostructured catalysts for efficient and selective CO2 electroreduction – synthesis, catalytic performance, and mechanistic analysis

Wang, Xingli (2020)

In the past decades, the atmospheric CO2 emissions increased with the unrestrained combustion of fossil fuels to meet the growing energy demand, leading to serious environmental pollution and climate issues. The electrochemical CO2 reduction reaction (CO2RR) is a promising alternative to convert CO2 into value-added products, and has the potential to contribute to a carbon-neutral energy cycle ...

Colloidal bimetallic platinum–ruthenium nanoparticles in ordered mesoporous carbon films as highly active electrocatalysts for the hydrogen evolution reaction

Sachse, René ; Bernsmeier, Denis ; Schmack, Roman ; Häusler, Ines ; Hertwig, Andreas ; Kraffert, Katrin ; Nissen, Jörg ; Krähnert, Ralph (2020-03-04)

Hydrogen features a very high specific energy density and is therefore a promising candidate for clean fuel from renewable resources. Water electrolysis can convert electrical energy into storable and transportable hydrogen gas. Under acidic conditions, platinum is the most active and stable monometallic catalyst for the hydrogen evolution reaction (HER). Yet, platinum is rare and needs to be u...

Graphene Quantum Dot-Based Electrochemical Immunosensors for Biomedical Applications

Mansuriya, Bhargav D. ; Altintas, Zeynep (2019-12-23)

In the area of biomedicine, research for designing electrochemical sensors has evolved over the past decade, since it is crucial to selectively quantify biomarkers or pathogens in clinical samples for the efficacious diagnosis and/or treatment of various diseases. To fulfil the demand of rapid, specific, economic, and easy detection of such biomolecules in ultralow amounts, numerous nanomateria...

Surface-sensitive adsorption of water and carbon dioxide on magnetite

Zaki, Eman Ahmed Ahmed Mohammed (2020)

The interaction of water with solid surfaces is important in many scientific fields such as corrosion, electrochemistry, geology, and heterogeneous catalysis. Chemistry at water/oxide interfaces plays a crucial role in surface's properties and reactivity. Employing model systems structurally and electronically characterized under well-defined conditions offers deep insights into the chemistry o...