Amelioration of the building blocks is a plausible approach to graft aerogels with distinguished properties while preserving the aerogel superiority. However, the incorporation of designated ...properties into metallic aerogels, especially catalytically beneficial morphologies and transition metal doping, still remains a challenge. Here, we report on the first case of an aerogel electrocatalyst composed entirely of alloyed PdNi hollow nanospheres (HNSs) with controllable chemical composition and shell thickness. The synergy of the transition metal doping, combined with the hollow building blocks and the three dimensional network structure make the PdNi HNS aerogels promising electrocatalysts towards ethanol oxidation, among which the Pd83Ni17 HNS aerogel shows a 5.6-fold enhanced mass activity compared to commercial Pd/C. This work expands the exploitation approach of electrocatalytic properties of aerogels into morphology and composition control of its building blocks.
Tri(pyrazolyl)phosphane (5R1,R2) werden als alternative, kostengünstige und geringer toxische Phosphorpräkursoren in der Synthese von InP/ZnS Quantenpunkten (QP) eingesetzt. Ausgehend von diesen ...Vorläuferverbindungen konnten langzeitstabile (>6 Monate) P(OLA)3 (OLAH = Oleylamin) Stammlösungen synthetisiert werden, aus denen sich die entsprechenden Pyrazole einfach zurückgewinnen lassen. P(OLA)3 fungiert in der Synthese von hochemittierenden InP/ZnS QP sowohl als Phosphorquelle als auch als Reduktionsmittel. Die erhaltenen Kern/Schale-Partikel zeichnen sich durch hohe Photolumineszenz-Quantenausbeuten (PL-QA) von 51–62% in einem spektralen Bereich von 530–620 nm aus. Die Verarbeitung und Anwendung dieser InP/ZnS QP als Farbkonversionsschicht wurde als „proof-of-concept“ in einer weißen Leuchtdiode (LED) demonstriert
A controlled assembly of natural beta-cyclodextrin modified Au NPs mediated by dopamine is demonstrated. Furthermore, a simple and sensitive colorimetric detection for dopamine is established by the ...concentration-dependent assembly.
Amelioration of the building blocks is a plausible approach to graft aerogels with distinguished properties while preserving the aerogel superiority. However, the incorporation of designated ...properties into metallic aerogels, especially catalytically beneficial morphologies and transition metal doping, still remains a challenge. Here, we report on the first case of an aerogel electrocatalyst composed entirely of alloyed PdNi hollow nanospheres (HNSs) with controllable chemical composition and shell thickness. The synergy of the transition metal doping, combined with the hollow building blocks and the three dimensional network structure make the PdNi HNS aerogels promising electrocatalysts towards ethanol oxidation, among which the Pd83Ni17 HNS aerogel shows a 5.6-fold enhanced mass activity compared to commercial Pd/C. This work expands the exploitation approach of electrocatalytic properties of aerogels into morphology and composition control of its building blocks.
A controlled assembly of natural beta-cyclodextrin modified Au NPs mediated by dopamine is demonstrated. Furthermore, a simple and sensitive colorimetric detection for dopamine is established by the ...concentration-dependent assembly.
Semiconductor nanostructures such as CdSe quantum dots and colloidal nanoplatelets exhibit remarkable optical properties, making them interesting for applications in optoelectronics and ...photocatalysis. For both areas of application a detailed understanding of the electronic structure is essential to achieve highly efficient devices. The electronic structure can be probed using the fact that optical properties of semiconductor nanoparticles are found to be extremely sensitive to the presence of excess charges that can for instance be generated by means of an electrochemical charge transfer via an electrode. Here we present the use of EMAS as a versatile spectroelectrochemical method to obtain absolute band edge positions of CdSe nanostructures versus a well-defined reference electrode under ambient conditions. In this, the spectral properties of the nanoparticles are monitored with respect to an applied electrochemical potential. We developed a bleaching model that yields the lowest electronic state in the conduction band of the nanostructures. A change in the band edge positions caused by quantum confinement is shown both for CdSe quantum dots and for colloidal nanoplatelets. In the case of CdSe quantum dots these findings are in good agreement with tight binding calculations. The method presented is not limited to CdSe nanostructures but can be used as a universal tool. Hence, this technique allows the determination of absolute band edge positions of a large variety of materials used in various applications
Tri(pyrazolyl)phosphanes (5R1,R2) are utilized as an alternative, cheap and low-toxic phosphorus source for the convenient synthesis of InP/ZnS quantum dots (QDs). From these precursors, remarkably ...long-term stable stock solutions (>6 months) of P(OLA)3 (OLAH = oleylamine) are generated from which the respective pyrazoles are conveniently recovered. P(OLA)3 acts simultaneously as phosphorus source and reducing agent in the synthesis of highly emitting InP/ZnS core/shell QDs. These QDs are characterized by a spectral range between 530–620 nm and photoluminescence quantum yields (PL QYs) between 51–62%. A proof-of-concept white light-emitting diode (LED) applying the InP/ZnS QDs as color conversion layer was built to demonstrate their applicability and processibility.
Structure, composition, and optical properties of colloidal mercaptoacetate-stabilized Cu2ZnSnS4 (CZTS) nanocrystal inks produced by a “green” method directly in aqueous solutions were characterized. ...A size-selective precipitation procedure using 2-propanol as a non-solvent allows separating a series of fractions of CZTS nanocrystals with an average size (bandgap) varying from 3 nm (1.72 eV) to 2 nm (2.04 eV). The size-selected CZTS nanocrystals revealed also phonon confinement, with the main phonon mode frequency varying by about 4 cm−1 between 2 nm and 3 nm NCs.
Highly active and durable oxygen reduction catalysts are needed to reduce the costs and enhance the service life of polymer electrolyte fuel cells (PEFCs). This can be accomplished by alloying Pt ...with a transition metal (e.g. Ni) and by eliminating the corrodible, carbon based catalyst support - however, materials combining both approaches have seldom been implemented in PEFC cathodes. In this work, an unsupported Pt-Ni alloy nanochain ensemble (aerogel) demonstrates high current PEFC performance commensurate with that of a carbon supported benchmark (Pt/C) following optimization of the aerogel\'s catalyst layer (CL) structure. The latter is accomplished using a soluble filler to shift the CL\'s pore size distribution towards larger pores which improves reactant and product transport. Chiefly, the optimized PEFC aerogel cathodes display ≈ 2.5-fold larger surface-specific ORR activity than Pt/C and maintain 90% of the initial activity after an accelerated stress test (vs. 40% for Pt/C).
In the present paper, the use of high aspect ratio metallic nanowires (NWs) as functional interconnects between three-dimensionally stacked chips is proposed. First practical preparation steps, as ...there are the preparation of templates and the deposition of Ag-NWs, are presented. Later on, the applicational technology for vertically aligned NWs is proposed as their embedment into a polymer matrix resulting in an anisotropically conductive composite film. This is discussed in both technological and functional aspects.
