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Pt-decorated $$\hbox {TiO}_{2}$$ nanotubes Pt@TiO2 are prepared only by applying a set of facile wet-chemical redox reactions to ion track-etched polycarbonate templates. First, a homogeneous layer of Pt nanoparticles is deposited onto the complex template surface by reducing potassium tetrachloroplatinate with absorbed dimethylaminoborane. Second, the template is coated with a conformal $$\hbox {TiO}_{2}$$ layer, using a chemical bath deposition reaction based on titanium(III) chloride. After the removal of the template, the rutile-type $$\hbox {TiO}_{2}$$ nanotubes remain decorated with Pt nanoparticles and nanoparticle-clusters on their outside. During the process, neither vacuum techniques nor external current sources or addition of heat are employed. The crystallinity, composition, and morphology of the composite nanotubes are analysed by X-ray diffraction, scanning and transmission electron microscopy as well as by energy-dispersive X-ray spectroscopy. Finally, the obtained materials are examplarily applied in the electrooxidation of ethanol and formic acid, and their performances have been evaluated. Compared to conventional carbon black-supported Pt nanoparticles, the Pt@TiO2 nanotubes show higher reaction rates. Mass activities of 2.36 $$\hbox {A}\hbox { mg}_{\rm Pt}^{-1}\hbox { cm}^{-2}$$ are reached in ethanol oxidation and 7.56 $$\hbox {A}\hbox { mg}_{\rm Pt}^{-1}\hbox { cm}^{-2}$$ in the formic acid oxidation. The present structures are able to exploit the synergy of Pt and $$\hbox {TiO}_{2}$$ with a bifunctional mechanism to result in powerful but easy-to-fabricate catalyst structures. They represent an easily producible type of composite nanostructures which can be applied in various fields such as in catalytics and sensor technology.

Electroless plating of metal films on polymer substrates usually requires the presence of metal particles acting as catalytically active nuclei for the deposition reaction. Herein, we present a novel and versatile approach towards the activation of polycarbonate substrates with metal nanoparticles. It is based on the diffusion of dimethylaminoborane into the polymer matrix, followed by reaction of the sensitized substrates with metal salt solutions. The reducing agent uptake was controlled by changing the duration of the sensitization and the dimethylaminoborane concentration in the sensitization solution. Different seed types (Ag, Au, Pd, Pt and Rh) were deposited by variation of the activation solution. The proposed mechanism was confirmed with FTIR and TEM measurements. In addition, AFM revealed that apart from a slight roughening in the nanometer range, the surface morphology of the polymer remained unchanged, rendering the method viable for template-based nanomaterial fabrication. Due to its pronounced variability, the new technique allows to tailor the activity of polymer substrates for consecutive electroless plating. The feasibility and nanoscale homogeneity of the process were proven by the electroless fabrication of well-defined Au and Pt nanotubes in ion-track etched polycarbonate templates. The combination of features (use of simple and easily scalable wet-chemical processes, facile seed variation, high activation quality on complex surfaces) renders the outlined technique promising for the fabrication of intricate nanomaterials as well as for the metallization of macroscopic work pieces.

The subcellular distribution of mercaptoundecahydro-closo-dodecaborate (BSH) in glioblastoma multiforme tissue sections of several patients having received BSH prior to surgery was investigated by transmission electron microscopy (TEM) using antibodies against BSH and electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI). These microscopic techniques show that BSH is associated with extracellular structures, the cell membrane as well as with the chromatin in the nucleus.