The gold electrode surface has been functionalized by phenyl groups ending with aminoethyl or carboxyethyl entities. The functionalization was achieved by the electrochemical reduction of 4-aminoethylbenzene- or 4-carboxyethylbenzene-diazonium salts. The laccase layers were studied by polarization modulation infrared spectroscopy (PMIRRAS), linear sweep voltammetry, and electrochemical quartz microbalance. The kind of surface groups controlling the orientation of the enzyme on the surface was revealed by PMIRRAS. The orientation influenced the enzyme activity on its turn. The direct, mediatorless electrocatalytic current due to the oxygen reduction was observed starting from +0.60 V versus Ag/AgCl at pH 4.5 for laccase immobilized on the amine-ended layer. The observed potential value is close to the redox potential of the laccase T1 center. The electrocatalytic current values were equal to 4 mA/cm. Immobilization of laccase on the carboxyethyl groups leads to smaller electrocatalytic current values. The onset of the electrocatalytic current was down-shifted to +0.56 V.

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This article describes a facile low-cost synthesis of polyaniline nanotube (PANINT)–carbon nano-onion (CNO) composites for solid-state supercapacitors. Scanning electron microscopic (SEM) analyses indicate a uniform and ordered composition for the conducting polymer nanotubes immobilized on a thin gold film. The obtained nanocomposites exhibit a brush-like architecture with a specific capacitance of 946 F g−1 at a scan rate of 1 mV s−1. In addition, the nanocomposites offer high conductivity and a porous and well-developed surface area. The PANINT–CNO nanocomposites were tested as electrodes with high potential and long-term stability for use in easy-to-miniaturize high-performance supercapacitor devices.

The correlation between the oxidation of single-walled carbon nanohorns (SWCNHs) via acid treatment and the electrochemical properties of the SWCNH electrodes is presented.

The Langmuir−Blodgett (LB) method has long been used for the preparation of ultrathin films, offering the unique control over the film thickness and the molecular orientation. Here, we report on the deposition and the characterization of LB layers of polyaniline (PANI) nanotubes on solid supports. Stable suspension of the nanotubes in chloroform was obtained by adding sodium dodecyl sulfate (SDS). The nanotubes to SDS ratio is important for the stability of the suspension. Langmuir films were spread at the water/air interface and transferred on gold or ITO glass substrate. The electroactivity of obtained films was investigated using cyclic voltammetry. The degree of assembly of the PANI nanotubes in thin films was characterized by optical microscopy and scanning electron microscopy (SEM). To evaluate the molecular structure and the PANI oxidation state, UV−vis and Raman mapping were used. The PANI nanotube films on the gold support are electroactive with cyclic voltammetry responses closely resembling typical PANI layers. Raman maps reveal that the spatial distributions of SDS and PANI bands are identical, suggesting that only detergent molecules bond to nanotubes are transferred on the support.

Strongly adhered layers of the compound with the primary amino group directed toward the solution were obtained at the gold surface by chronoamperometric electroreduction of 4-aminoethylobenzenodiazonium salt (AEBD) in acetonitrile solution at appropriately selected potential. The used techniques (EQCM, AFM, EIS, PM, IRRAS) showed that the nature and thickness of formed aminoethylophenyl layer strongly depend on the potential applied to the electrode. Electroreduction of AEBD salt at a potential more negative than -0.6 V (vs Ag/AgCl) leads to about monolayer on the gold surface. Additionally, such a layer was very tight and uniform. The electrochemical measurements indicate that the efficient and precise attachment of biomolecules to the aminoethylophenyl layer is only possible when this layer is formed at appropriate potential. This was shown for ss- and dsDNA.

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: This article presents a brief review of the knowledge concerning onion-like carbons (OLCs). These nanostructures are some of the most fascinating carbon forms due to their unusual structure and physico-chemical properties. Generally, OLCs consist of a hollowspherical fullerene core surrounded by concentric graphitic layers with increasing diameter. Nevertheless, they can have different size, shape and type of core, which determine their physicochemical properties. In this article, we review the most important literature reports in this area and briefly describe these nanostructures, their physical and chemical properties and their potential uses with a focus on biomedicine.