Refine
Has Fulltext
- no (4)
Document Type
- Article (4)
Language
- English (4)
Is part of the Bibliography
- yes (4)
Keywords
- inverse micelles (2)
- nanoreactor (2)
- polystyrene-block-poly(4-vinylpyridine) (2)
- soft-templating (2)
- tin-rich ITO (2)
- yolk@shell materials (2)
- AgAu alloy nanoparticles (1)
- TiO2 nanotubes (1)
- bioelectrochemistry (1)
- cytochrome c (1)
Institute
We present the fabrication of TiO2 nanotube electrodes with high biocompatibility and extraordinary spectroscopic properties. Intense surface-enhanced resonance Raman signals of the heme unit of the redox enzyme Cytochromeb(5) were observed upon covalent immobilization of the protein matrix on the TiO2 surface, revealing overall preserved structural integrity and redox behavior. The enhancement factor could be rationally controlled by varying the electrode annealing temperature, reaching a record maximum value of over 70 at 475 degrees C. For the first time, such high values are reported for non-directly surface-interacting probes, for which the involvement of charge-transfer processes in signal amplification can be excluded. The origin of the surface enhancement is exclusively attributed to enhanced localized electric fields resulting from the specific optical properties of the nanotubular geometry of the electrode.
Yolk@Shell Nanoarchitectures with Bimetallic Nanocores - Synthesis and Electrocatalytic Applications
(2016)
Due to their unique morphology-related properties, yolk@shell materials are promising materials for catalysis, drug delivery, energy conversion, and storage. Despite their proven potential, large-scale applications are however limited due to demanding synthesis protocols. Overcoming these limitations, a simple soft-templated approach for the one-pot synthesis of yolk@shell nanocomposites and in particular of multicore metal nanoparticle@metal oxide nanostructures (M-NP@MOx) is introduced. The approach here, as demonstrated for Au-NP@ITOTR (ITOTR standing for tin-rich ITO), relies on polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) inverse micelles as two compartment nanoreactor templates. While the hydrophilic P4VP core incorporates the hydrophilic metal precursor, the hydrophobic PS corona takes up the hydrophobic metal oxide precursor. As a result, interfacial reactions between the precursors can take place, leading to the formation of yolk@shell structures in solution. Once calcined these micelles yield Au-NP@ITOTR nanostructures, composed of multiple 6 nm sized Au NPs strongly anchored onto the inner surface of porous 35 nm sized ITOTR hollow spheres. Although of multicore nature, only limited sintering of the metal nanoparticles is observed at high temperatures (700 degrees C). In addition, the as-synthesized yolk@shell structures exhibit high and stable activity toward CO electrooxidation, thus demonstrating the applicability of our approach for the design of functional yolk@shell nanocatalysts.
The preparation of porous, i.e., high surface area electrodes from transparent conducting oxides, is a valuable goal in materials chemistry as such electrodes can enable further development of optoelectronic, electrocatalytic, or bioelectronic devices. In this work the first tin-rich mesoporous indium tin oxide is prepared using the molecular heterobimetallic single-source precursor, indium tin tris-tert-butoxide, together with an appropriate structure-directing template, yielding materials with high surface areas and tailorable pore size. The resulting mesoporous tin-rich ITO films show a high and durable electrical conductivity and transparency, making them interesting materials for hosting electroactive biomolecules such as proteins. In fact, its unique performance in bioelectronic applications has been demonstrated by immobilization of high amounts of cytochrome c into the mesoporous film which undergo redox processes directly with the conductive electrode material.