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A paper from cfaed's Chair for Molecular Functional Materials co-authored by researchers at universities and institutes in Germany, France and Japan has been published in Nature Communications on 17th May 2017. The paper titled "Efficient hydrogen production on MoNi4 electrocatalysts with fast water dissociation kinetics" describes a new approach to revolutionize the production of molecular hydrogen. This gas is considered to be one of the most promising energy carriers of the future. Growing concern about the energy crisis and the seriousness of environmental contamination urgently demand the development of renewable energy sources as feasible alternatives to diminishing fossil fuels. Owing to its high energy density and environmentally friendly characteristics, molecular hydrogen is an attractive and promising energy carrier to meet future global energy demands. In many of the approaches for hydrogen production, the electrocatalytic hydrogen evolution reaction (HER) from water splitting is the most economical and effective route for the future hydrogen economy. To accelerate the sluggish HER kinetics, particularly in alkaline electrolytes, highly active and durable electrocatalysts are essential to lower the kinetic HER overpotential. As a benchmark HER electrocatalyst with a zero HER overpotential, the precious metal platinum (Pt) plays a dominant role in present H2-production technologies, such as water-alkali electrolysers. Unfortunately, the scarcity and high cost of Pt seriously impede its large-scale applications in electrocatalytic HERs. Prof. Xinliang Feng's team from the Technische Universität Dresden (Germany)/ Center for Advancing Electronics Dresden (cfaed), in collaboration with the University Lyon, ENS de Lyon, Centre national de la recherche scientifique (CNRS, France), the Tohoku University (Japan) and the Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) (Germany), have reported a low-cost MoNi4 electrocatalyst anchored on MoO2 cuboids, which are vertically aligned on nickel foam (MoNi4/MoO2@Ni). MoNi4 nanoparticles are constructed in situ on the MoO2 cuboids by controlling the outward diffusion of Ni atoms. The resultant MoNi4/MoO2@Ni exhibits a high HER activity that is highly comparable to that of the Pt catalyst and presents state-of-the-art HER activity amongst all reported Pt-free electrocatalysts. Experimental investigations reveal that the MoNi4 electrocatalyst behaves as the highly active centre and manifests fast Tafel step-determined HER kinetics. Furthermore, density functional theory (DFT) calculations determine that the kinetic energy barrier of the Volmer step for the MoNi4 electrocatalyst is greatly decreased. The large-scale preparation and excellent catalytic stability provide MoNi4/MoO2@Ni with a promising utilization in water-alkali electrolysers for hydrogen production. Therefore, the exploration and understanding of the MoNi4 electrocatalyst provide a promising alternative to Pt catalysts for emerging applications in energy generation.


News Article | May 19, 2017
Site: www.rdmag.com

Growing concern about the energy crisis and the seriousness of environmental contamination urgently demand the development of renewable energy sources as feasible alternatives to diminishing fossil fuels. Owing to its high energy density and environmentally friendly characteristics, molecular hydrogen is an attractive and promising energy carrier to meet future global energy demands. In many of the approaches for hydrogen production, the electrocatalytic hydrogen evolution reaction (HER) from water splitting is the most economical and effective route for the future hydrogen economy. To accelerate the sluggish HER kinetics, particularly in alkaline electrolytes, highly active and durable electrocatalysts are essential to lower the kinetic HER overpotential. As a benchmark HER electrocatalyst with a zero HER overpotential, the precious metal platinum (Pt) plays a dominant role in present H2-production technologies, such as water-alkali electrolysers. Unfortunately, the scarcity and high cost of Pt seriously impede its large-scale applications in electrocatalytic HERs. Prof. Xinliang Feng's team from the Technische Universität Dresden (Germany)/ Center for Advancing Electronics Dresden (cfaed), in collaboration with the University Lyon, ENS de Lyon, Centre national de la recherche scientifique (CNRS, France), the Tohoku University (Japan) and the Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) (Germany), have reported a low-cost MoNi4 electrocatalyst anchored on MoO2 cuboids, which are vertically aligned on nickel foam (MoNi4/MoO2@Ni). MoNi4 nanoparticles are constructed in situ on the MoO2 cuboids by controlling the outward diffusion of Ni atoms. The resultant MoNi4/MoO2@Ni exhibits a high HER activity that is highly comparable to that of the Pt catalyst and presents state-of-the-art HER activity amongst all reported Pt-free electrocatalysts. Experimental investigations reveal that the MoNi4 electrocatalyst behaves as the highly active centre and manifests fast Tafel step-determined HER kinetics. Furthermore, density functional theory (DFT) calculations determine that the kinetic energy barrier of the Volmer step for the MoNi4 electrocatalyst is greatly decreased. The large-scale preparation and excellent catalytic stability provide MoNi4/MoO2@Ni with a promising utilization in water-alkali electrolysers for hydrogen production. Therefore, the exploration and understanding of the MoNi4 electrocatalyst provide a promising alternative to Pt catalysts for emerging applications in energy generation.


In many of the approaches for hydrogen production, the electrocatalytic hydrogen evolution reaction (HER) from water splitting is the most economical and effective route for the future hydrogen economy. To accelerate the sluggish HER kinetics, particularly in alkaline electrolytes, highly active and durable electrocatalysts are essential to lower the kinetic HER overpotential. As a benchmark HER electrocatalyst with a zero HER overpotential, the precious metal platinum (Pt) plays a dominant role in present H2-production technologies, such as water-alkali electrolysers. Unfortunately, the scarcity and high cost of Pt seriously impede its large-scale applications in electrocatalytic HERs. Prof. Xinliang Feng's team from the Technische Universität Dresden (Germany)/ Center for Advancing Electronics Dresden (cfaed), in collaboration with the University Lyon, ENS de Lyon, Centre national de la recherche scientifique (CNRS, France), the Tohoku University (Japan) and the Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) (Germany), have reported a low-cost MoNi4 electrocatalyst anchored on MoO2 cuboids, which are vertically aligned on nickel foam (MoNi4/MoO2@Ni). MoNi4 nanoparticles are constructed in situ on the MoO2 cuboids by controlling the outward diffusion of Ni atoms. The resultant MoNi4/MoO2@Ni exhibits a high HER activity that is highly comparable to that of the Pt catalyst and presents state-of-the-art HER activity amongst all reported Pt-free electrocatalysts. Experimental investigations reveal that the MoNi4 electrocatalyst behaves as the highly active centre and manifests fast Tafel step-determined HER kinetics. Furthermore, density functional theory (DFT) calculations determine that the kinetic energy barrier of the Volmer step for the MoNi4 electrocatalyst is greatly decreased. The large-scale preparation and excellent catalytic stability provide MoNi4/MoO2@Ni with a promising utilization in water-alkali electrolysers for hydrogen production. Therefore, the exploration and understanding of the MoNi4 electrocatalyst provide a promising alternative to Pt catalysts for emerging applications in energy generation. Explore further: Promising results obtained with a new electrocatalyst that reduces the need for platinum More information: Jian Zhang et al. Efficient hydrogen production on MoNi4 electrocatalysts with fast water dissociation kinetics, Nature Communications (2017). DOI: 10.1038/NCOMMS15437


News Article | May 19, 2017
Site: www.eurekalert.org

Growing concern about the energy crisis and the seriousness of environmental contamination urgently demand the development of renewable energy sources as feasible alternatives to diminishing fossil fuels. Owing to its high energy density and environmentally friendly characteristics, molecular hydrogen is an attractive and promising energy carrier to meet future global energy demands. In many of the approaches for hydrogen production, the electrocatalytic hydrogen evolution reaction (HER) from water splitting is the most economical and effective route for the future hydrogen economy. To accelerate the sluggish HER kinetics, particularly in alkaline electrolytes, highly active and durable electrocatalysts are essential to lower the kinetic HER overpotential. As a benchmark HER electrocatalyst with a zero HER overpotential, the precious metal platinum (Pt) plays a dominant role in present H2-production technologies, such as water-alkali electrolysers. Unfortunately, the scarcity and high cost of Pt seriously impede its large-scale applications in electrocatalytic HERs. Prof. Xinliang Feng's team from the Technische Universität Dresden (Germany)/ Center for Advancing Electronics Dresden (cfaed), in collaboration with the University Lyon, ENS de Lyon, Centre national de la recherche scientifique (CNRS, France), the Tohoku University (Japan) and the Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) (Germany), have reported a low-cost MoNi4 electrocatalyst anchored on MoO2 cuboids, which are vertically aligned on nickel foam (MoNi4/MoO2@Ni). MoNi4 nanoparticles are constructed in situ on the MoO2 cuboids by controlling the outward diffusion of Ni atoms. The resultant MoNi4/MoO2@Ni exhibits a high HER activity that is highly comparable to that of the Pt catalyst and presents state-of-the-art HER activity amongst all reported Pt-free electrocatalysts. Experimental investigations reveal that the MoNi4 electrocatalyst behaves as the highly active centre and manifests fast Tafel step-determined HER kinetics. Furthermore, density functional theory (DFT) calculations determine that the kinetic energy barrier of the Volmer step for the MoNi4 electrocatalyst is greatly decreased. The large-scale preparation and excellent catalytic stability provide MoNi4/MoO2@Ni with a promising utilization in water-alkali electrolysers for hydrogen production. Therefore, the exploration and understanding of the MoNi4 electrocatalyst provide a promising alternative to Pt catalysts for emerging applications in energy generation. This work was financially supported by the ERC Grant on 2DMATER and EC under Graphene Flagship (No. CNECT-ICT-604391). cfaed is a microelectronics research cluster funded by the German Excellence Initiative. It comprises 11 cooperating institutes in Saxony. About 300 scientists from more than 20 countries investigate new technologies for electronic information processing. These technologies are inspired by innovative materials such as silicon nanowires, carbon nanotubes or polymers or based on completely new concepts such as the chemical chip or circuit fabrication methods by self-assembling structures such as DNA-Origami. The orchestration of these new devices into heterogeneous information processing systems with focus on their resilience and energy-efficiency is also part of cfaed's research program which comprises nine different research paths.


Weber C.A.,Max Planck Institute for the Physics of Complex Systems | Weber C.A.,Center for Advancing Electronics Dresden | Lee C.F.,Imperial College London | Julicher F.,Max Planck Institute for the Physics of Complex Systems | Julicher F.,Center for Advancing Electronics Dresden
New Journal of Physics | Year: 2017

Living cells use phase separation and concentration gradients to organize chemical compartments in space. Here, we present a theoretical study of droplet dynamics in gradient systems. We derive the corresponding growth law of droplets and find that droplets exhibit a drift velocity and position dependent growth. As a consequence, the dissolution boundary moves through the system, thereby segregating droplets to one end. We show that for steep enough gradients, the ripening leads to a transient arrest of droplet growth that is induced by a narrowing of the droplet size distribution. © 2017 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.


Ceylan I.I.,TU Dresden | Penaloza R.,TU Dresden | Penaloza R.,Center for Advancing Electronics Dresden
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

We introduce the probabilistic Description Logic. In, axioms are required to hold only in an associated context. The probabilistic component of the logic is given by a Bayesian network that describes the joint probability distribution of the contexts. We study the main reasoning problems in this logic; in particular, we (i) prove that deciding positive and almost-sure entailments is not harder for than for the BN, and (ii) show how to compute the probability, and the most likely context for a consequence. © 2014 Springer International Publishing Switzerland.


Borchmann D.,TU Dresden | Borchmann D.,Center for Advancing Electronics Dresden
Lecture Notes in Artificial Intelligence (Subseries of Lecture Notes in Computer Science) | Year: 2015

Within formal concept analysis, attribute exploration is a powerful tool to semi-automatically check data for completeness with respect to a given domain. However, the classical formulation of attribute exploration does not take into account possible errors which are present in the initial data. To remedy this, we present in this work a generalization of attribute exploration based on the notion of confidence, that will allow for the exploration of implications which are not necessarily valid in the initial data, but instead enjoy a minimal confidence therein. © 2015 Springer International Publishing Switzerland.


Borgwardt S.,TU Dresden | Distel F.,TU Dresden | Penaloza R.,TU Dresden | Penaloza R.,Center for Advancing Electronics Dresden
Artificial Intelligence | Year: 2015

Fuzzy description logics (DLs) can be used to represent and reason with vague knowledge. This family of logical formalisms is very diverse, each member being characterized by a specific choice of constructors, axioms, and triangular norms, which are used to specify the semantics. Unfortunately, it has recently been shown that the consistency problem in many fuzzy DLs with general concept inclusion axioms is undecidable. In this paper, we present a proof framework that allows us to extend these results to cover large classes of fuzzy DLs. On the other hand, we also provide matching decidability results for most of the remaining logics. As a result, we obtain a near-universal classification of fuzzy DLs according to the decidability of their consistency problem. © 2014 Elsevier B.V. All rights reserved.


Borgwardt S.,TU Dresden | Penaloza R.,TU Dresden | Penaloza R.,Center for Advancing Electronics Dresden
International Journal of Approximate Reasoning | Year: 2014

Fuzzy Description Logics have been widely studied as a formalism for representing and reasoning with vague knowledge. One of the most basic reasoning tasks in (fuzzy) Description Logics is to decide whether an ontology representing a knowledge domain is consistent. Surprisingly, not much is known about the complexity of this problem for semantics based on complete De Morgan lattices. To cover this gap, in this paper we study the consistency problem for the fuzzy Description Logic L-SHI and its sublogics in detail. The contribution of the paper is twofold. On the one hand, we provide a tableaux-based algorithm for deciding consistency when the underlying lattice is finite. The algorithm generalizes the one developed for classical SHI. On the other hand, we identify decidable and undecidable classes of fuzzy Description Logics over infinite lattices. For all the decidable classes, we also provide tight complexity bounds. © 2013 Elsevier Inc.


Borgwardt S.,TU Dresden | Penaloza R.,TU Dresden | Penaloza R.,Center for Advancing Electronics Dresden
IJCAI International Joint Conference on Artificial Intelligence | Year: 2013

The Description Logic EL is used to formulate several large biomedical ontologies. Fuzzy extensions of EL can express the vagueness inherent in many biomedical concepts. We study the reasoning problem of deciding positive subsumption in fuzzy EL with semantics based on general t-norms. We show that the complexity of this problem depends on the specific t-norm chosen. More precisely, if the t-norm has zero divisors, then the problem is co-NP-hard; otherwise, it can be decided in polynomial time. We also show that the best subsumption degree cannot be computed in polynomial time if the t-norm contains the Łukasiewicz t-norm.

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