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Stimulated-healing of proton exchange membrane fuel cell catalyst

Latsuzbaia, R. (author), Negro, E. (author), Koper, G.J.M. (author)

Platinum nanoparticles, which are used as catalysts in Proton Exchange Membrane Fuel Cells (PEMFC), tend to degrade after long-term operation. We discriminate the following mechanisms of the degradation: poisoning, migration and coalescence, dissolution, and electrochemical Ostwald ripening. There are two ways to tackle this problem. The first...

conference paper 2013

document

Networked Graphitic Structures Grown from Dense Microemulsions as High Performance Electrode Material (abstract)

Negro, E. (author), Dieci, M. (author), Sordi, D. (author), Koper, G.J.M. (author)

conference paper 2013

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Dissipative self-assembly: A novel self-healing mechanism for functional materials

Koper, G.J.M. (author), Boekhoven, J. (author), Hendriksen, W.E. (author), Eelkema, R. (author), Van Esch, J.H. (author)

Self-assembled systems formed of micelles or vesicles have frequently been discussed as model systems for self-healing materials because their structure is dictated by thermodynamics and hence they quickly restore upon perturbation. In this aspect, they mimic many natural systems such as biological cells. However, in contrast to most synthetic...

conference paper 2013

document

Synthesis of Durable Platinum Catalyst for Proton Exchange Membrane Fuel Cells in Bicontinuous Microemulsion (abstract)

Latsuzbaia, R. (author), Nergo, E. (author), Koper, G.J.M. (author)

conference paper 2013

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Reversible Nanoparticle Formation As a Potential Strategy for PEMFC Catalyst Regeneration (abstract)

Latsuzbaia, R. (author), Negro, E. (author), Koper, G.J.M. (author)

conference paper 2013

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Covalently, Non-Covalently and Non Functionalized Networked Graphitic Structures as robust catalyst support in PEM electrodes (abstract)

Negro, E. (author), De Vries, M. (author), Latsuzbaia, R. (author), Koper, G.J.M. (author)

conference paper 2013

document

Towards Evaluating Stream Processing Autoscalers

Siachamis, G. (author), Kanis, Job (author), Koper, Wybe (author), Psarakis, K. (author), Fragkoulis, M. (author), van Deursen, A. (author), Katsifodimos, A (author)

In this work, we evaluate autoscaling solutions for stream processing engines. Although autoscaling has become a mainstream subject of research in the last decade, the database research community has yet to evaluate different autoscaling techniques under a proper benchmarking setting and evaluation framework. As a result, every newly proposed...

conference paper 2023

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High yield, controlled synthesis of graphitic networks from dense micro emulsions

Negro, E. (author), Dieci, M. (author), Sordi, D. (author), Kowlgi, K. (author), Makkee, M. (author), Koper, G.J.M. (author)

We report on the production of Carbon Nano Networks (CNNs) from dense microemulsions in which catalyst nanoparticles have been synthesized. CNNs are 3D carbon networks, consisting of branches and junctions, and are mesoporous, graphitic, and conductive being suitable as electrode materials.

journal article 2014

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Bicontinuous microemulsions for high yield, wet synthesis of ultrafine nanoparticles: A general approach

Latsuzbaia, R. (author), Negro, E. (author), Koper, G.J.M. (author)

The design of a synthesis strategy for metal nanoparticles by templating dense microemulsions is proposed. Particle size is controlled by surfactant size rather than by microemulsion composition. The strategy was demonstrated with various systems with different surfactant: cationic, anionic and non-ionic and of different sizes. Formulations were...

journal article 2015

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Proton binding by linear, branched, and hyperbranched polyelectrolytes

Koper, G.J.M. (author), Borkovec, M. (author)

This article reviews our understanding of ionization processes of weak polyelectrolytes. The emphasis is put on a general introduction to site binding models, which are able to account for many experimental features of linear and branched polyelectrolytes, including dendrimers. These models are fully compatible with the classical description of...

journal article 2010

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Optimal ionic strength for nonionically initiated polymerization

Dobrowolska, M.E. (author), Koper, G.J.M. (author)

Surfactant-free emulsion polymerization involving a nonionic, and hence uncharged initiator presents a new approach towards environmentally friendly procedures to synthesize latex particles. Under optimal solvent conditions, notably pH and ionic strength, the latex particles are stabilized by the natural development of ionic charge at the...

journal article 2013

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How to Determine the Core-Shell Nature in Bimetallic Catalyst Particles?

Westsson, E.E. (author), Koper, G.J.M. (author)

Nanometer-sized materials have significantly different chemical and physical properties compared to bulk material. However, these properties do not only depend on the elemental composition but also on the structure, shape, size and arrangement. Hence, it is not only of great importance to develop synthesis routes that enable control over the...

journal article 2014

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Stick-Slip Transition at the Nanometer Scale

Cheikh, C. (author), Koper, G. (author)

journal article 2003

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Slow growth of the Rayleigh-Plateau instability in aqueous two phase systems

Geschiere, S.D. (author), Ziemecka, I. (author), Van Steijn, V. (author), Koper, G.J.M. (author), Van Esch, J.H. (author), Kreutzer, M.T. (author)

This paper studies the Rayleigh-Plateau instability for co-flowing immiscible aqueous polymer solutions in a microfluidic channel. Careful vibration-free experiments with controlled actuation of the flow allowed direct measurement of the growth rate of this instability. Experiments for the well-known aqueous two phase system (ATPS, or aqueous...

journal article 2012

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Experimental and molecular dynamics characterization of dense microemulsion systems: Morphology, conductivity and SAXS

Negro, E. (author), Latsuzbaia, R. (author), De Vries, A.H. (author), Koper, G.J.M. (author)

Microemulsions are exciting systems that are promising as tuneable self-assembling templating reaction vessels at the nanoscale. Determination of the nano-structure of microemulsions is, however, not trivial, and there are fundamental questions regarding their design. We were able to reproduce experimental data for an important microemulsion...

journal article 2014

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Electrocatalytic Activity and Durability of Pt-Decorated Non-Covalently Functionalized Graphitic Structures

Negro, E. (author), Stassi, A. (author), Baglio, V. (author), Arico, A.S. (author), Koper, G.J.M. (author)

Carbon graphitic structures that differ in morphology, graphiticity and specific surface area were used as support for platinum for Oxygen Reduction Reaction (ORR) in low temperature fuel cells. Graphitic supports were first non-covalently functionalized with pyrene carboxylic acid (PCA) and, subsequently, platinum nanoparticles were nucleated...

journal article 2015

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Effects of Substrate and Polymer Encapsulation on CO₂ Electroreduction by Immobilized Indium(III) Protoporphyrin

Birdja, Yuvraj Y. (author), Vos, Rafaël E. (author), Wezendonk, T.A. (author), Jiang, Lin (author), Kapteijn, F. (author), Koper, M.T.M. (author)

Heterogenization of molecular catalysts for CO₂ electroreduction has attracted significant research activity, due to the combined advantages of homogeneous and heterogeneous catalysts. In this work, we demonstrate the strong influence of the nature of the substrate on the selectivity and reactivity of electrocatalytic CO<sub>2</sub...

journal article 2018

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The Glass Transition Temperature of Heterogeneous Biopolymer Systems

Pereira Espíndola, S. (author), Norder, B. (author), Koper, G.J.M. (author), Picken, S.J. (author)

Biopolymers are abundant, renewable, and biodegradable resources. However, bio-based materials often require toughening additives, like (co)polymers or small plasticizing molecules. Plasticization is monitored via the glass transition temperature versus diluent content. To describe this, several thermodynamic models exist; nevertheless, most...

journal article 2023

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Intermediate stages of electrochemical oxidation of single-crystalline platinum revealed by in situ Raman spectroscopy

Huang, Yi Fan (author), Kooyman, P.J. (author), Koper, M.T.M. (author)

Understanding the atomistic details of how platinum surfaces are oxidized under electrochemical conditions is of importance for many electrochemical devices such as fuel cells and electrolysers. Here we use in situ shell-isolated nanoparticle-enhanced Raman spectroscopy to identify the intermediate stages of the electrochemical oxidation of...

journal article 2016

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Iridium-based double perovskites for efficient water oxidation in acid media

Diaz-Morales, Oscar (author), Raaijman, Stefan (author), Kortlever, Ruud (author), Kooyman, P.J. (author), Wezendonk, T.A. (author), Gascon, Jorge (author), Fu, W. (author), Koper, M.T.M. (author)

The development of active, cost-effective and stable oxygen-evolving catalysts is one of the major challenges for solar-to-fuel conversion towards sustainable energy generation. Iridium oxide exhibits the best available compromise between catalytic activity and stability in acid media, but it is prohibitively expensive for large-scale...

journal article 2016