Ikerbasque

About: Ikerbasque is a other organization based out in Bilbao, Spain. It is known for research contribution in the topics: Graphene & Quantum. The organization has 713 authors who have published 7967 publications receiving 231990 citations. The organization is also known as: Basque Foundation for Science.

Chiral and Achiral Nanodumbbell Dimers: The Effect of Geometry on Plasmonic Properties.

Abstract: Metal nanoparticles with a dumbbell-like geometry have plasmonic properties similar to those of their nanorod counterparts, but the unique steric constraints induced by their enlarged tips result in distinct geometries when self-assembled. Here, we investigate gold dumbbells that are assembled into dimers within polymeric micelles. A single-particle approach with correlated scanning electron microscopy and dark-field scattering spectroscopy reveals the effects of dimer geometry variation on the scattering properties. The dimers are prepared using exclusively achiral reagents, and the resulting dimer solution produces no detectable ensemble circular dichroism response. However, single-particle circular differential scattering measurements uncover that this dimer sample is a racemic mixture of individual nanostructures with significant positive and negative chiroptical signals. These measurements are complemented with detailed simulations that confirm the influence of various symmetry elements on the overal...

Single-Chain Polymer Nanoparticles via Non-Covalent and Dynamic Covalent Bonds

Abstract: The added value behind reversible bonds is the possibility to develop responsive structurally dynamic materials, which can adapt their constitution and, hence, properties to external stimuli. In recent years, much effort has been devoted to the design and synthesis of single-chain polymer nanoparticles (SCNPs) that can be reversibly assembled or disassembled in response to external environmental changes or that can adapt even their structure through simple exchange reactions. Here, the evolution of the relatively new field of responsive SCNPs constructed via non-covalent, or supramolecular, interactions, and “dynamic” covalent bonds is described in detail. The main reversible bonds commonly used in supramolecular polymer chemistry and dynamic covalent materials are summarized. A detailed description of the current reported routes to reversible unimolecular polymer nanoparticles is provided. Finally, future prospects of SCNPs constructed via supramolecular interactions and dynamic bonds are detailed.

Co-axial heterostructures integrating palladium/titanium dioxide with carbon nanotubes for efficient electrocatalytic hydrogen evolution

Abstract: Considering the depletion of fossil-fuel reserves and their negative environmental impact, new energy schemes must point towards alternative ecological processes. Efficient hydrogen evolution from water is one promising route towards a renewable energy economy and sustainable development. Here we show a tridimensional electrocatalytic interface, featuring a hierarchical, co-axial arrangement of a palladium/titanium dioxide layer on functionalized multi-walled carbon nanotubes. The resulting morphology leads to a merging of the conductive nanocarbon core with the active inorganic phase. A mechanistic synergy is envisioned by a cascade of catalytic events promoting water dissociation, hydride formation and hydrogen evolution. The nanohybrid exhibits a performance exceeding that of state-of-the-art electrocatalysts (turnover frequency of 15000 H2 per hour at 50 mV overpotential). The Tafel slope of ∼130 mV per decade points to a rate-determining step comprised of water dissociation and formation of hydride. Comparative activities of the isolated components or their physical mixtures demonstrate that the good performance evolves from the synergistic hierarchical structure. Hydrogen evolution by water electrolysis is a promising route to 'green energy', but efficiency is still an issue. Here, the authors make mixed organic/inorganic hierarchical nanostructures with high hydrogen evolution activity, identifying synergic effects in the material contributing to enhanced efficiency.

Biodegradation of a simulated textile effluent by immobilised-coated laccase in laboratory-scale reactors

Abstract: Laccase from Trametes pubescens was immobilised on alumina pellets and coated with polyelectrolytes. It was shown that this approach enhanced both laccase stability and reusability. Further, the immobilised-coated laccase was applied to the decolouration of a simulated textile effluent in laboratory-scale reactors. The simulated textile effluent was based on the recalcitrant diazo dye Reactive Black 5 (0.5 g/L). It was found that the decolouration was due to two processes: dye adsorption on the immobilisation support and coating and dye degradation by the laccase enzyme. The adsorption process represented less than 10% of colour removal for all cases, so decolouration was mainly due to laccase action. The decolouration was performed in both batch and continuous modes. A complete decolouration of the effluent was obtained in 30–36 h for the former and 48 h for the latter without the addition of redox mediators. In addition, the decolourised effluent showed lower phytotoxicity than the original one. These encouraging results make the process suitable for its potential implementation at industrial scale.

Experimental Verification of PbBi2Te4 as a 3D Topological Insulator

Abstract: The experimental evidence is presented of the topological insulator state in PbBi2Te4. A single surface Dirac cone is observed by angle-resolved photoemission spectroscopy with synchrotron radiation. Topological invariants Z2 are calculated from the ab initio band structure to be 1;(111). The observed two-dimensional isoenergy contours in the bulk energy gap are found to be the largest among the known three-dimensional topological insulators. This opens a pathway to achieving a sufficiently large spin current density in future spintronic devices.