Here, we report on a novel nonenzymatic amperometric glucose sensor based on three-dimensional PtPb networks directly grown on Ti substrates using a reproducible one-step hydrothermal method. The surface morphology and bimetallic composition of the synthesized nanoporous PtPb materials were characterized using scanning electron microscopy and energy-dispersive X-ray spectrometry, respectively. Voltammetry and amperometric methods were used to evaluate the electrocatalytic activities of the synthesized electrodes toward nonenzymatic glucose oxidation in neutral media in the absence and in the presence of chloride ions. The synthesized nanoporous PtPb electrodes have strong and sensitive current responses to glucose. Their amperometric sensitivities increase in the order of Pt-Pb (0%) < Pt-Pb (30%) < Pt-Pb (70%) < Pt-Pb (50%). These nanoporous PtPb electrodes are also highly resistant toward poisoning by chloride ions and capable of sensing glucose amperometrically at a very low potential, -80 mV (Ag/AgCl), where the interference from the oxidation of common interfering species such as ascorbic acid, acetamidophenol, and uric acid is effectively avoided.

We report on a novel and facile approach for the direct growth of F-doped flower-like TiO(2) nanostructures on the surface of Ti in HF solutions under low-temperature hydrothermal conditions. The influence of the experimental parameters such as temperature, reaction duration, and the HF concentration on the morphology and photoelectrocatalytic activity of the formed F-doped flower-like TiO(2) nanostructures was systematically studied. The presence of HF and the reaction time play an important role in the formation of the F-doped flower-like TiO(2) nanostructures. The synthesized novel F-doped TiO(2) flower-like nanomaterials possess good crystallinity and exhibit high photoelectrochemical activity for water-splitting and photodegradation of organic pollutants compared with P-25, which is currently considered to be one of the best commercial TiO(2) photocatalysts. The approach described in this study provides a simple and novel method to synthesize F-doped TiO(2) nanostructured materials that are ready for practical applications such as the photodegradation of wastewater.

No abstract

We report on a facile and environment-friendly route to synthesize intermetallic PtPb nanodendrites with controllable compositions. This involves a hydrothermal-assisted coreduction of Pt and Pb inorganic precursors by formic acid in aqueous solutions without the use of any surfactant or polymer. Our systematic structural characterization and in situ electrochemical infrared spectroscopic studies of the formed PtPb nanodendrites reveal that the underlying morphogenesis, resulting from the intermetallic phase evolution from a Pt-based face-centered cubic to a PtPb hexagonal type, is responsible for the significant improvement of electrocatalytic activities toward the electrochemical oxidation of formic acid. A foreign-particlesinduced growth mechanism is proposed to account for the underlying dendritic growth process. The facile approach described in this study is further demonstrated to be universal for growing a variety of intermetallic nanodendrites, thus opening a door to develop and study novel nanodendritic materials.

A simple and facile method is described to directly synthesize TiO(2) nanostructures on titanium substrates by oxidizing Ti foil using small organic molecules as the oxygen source. The effect of reaction temperature and oxygen source on the formation of the TiO(2) nanostructures has been studied using scanning electron microscopy, x-ray diffraction, transmission electron microscopy, Raman spectroscopy and water contact angle measurement. Polycrystalline grains are formed when pure oxygen and formic acid are used as the oxygen source; elongated micro-crystals are produced when water vapour is used as the oxygen source; oriented and aligned TiO(2) nanorod arrays are synthesized when ethanol, acetaldehyde or acetone are used as the oxygen source. The growth mechanism of the TiO(2) nanostructures is discussed. The diffusion of Ti atoms to the oxide/gas interface via the network of the grain boundaries of the thin oxide layer is the determining factor for the formation of well-aligned TiO(2) nanorod arrays. The wetting properties of the TiO(2) nanostructured surfaces formed are dictated by their structure, varying from a hydrophilic surface to a strongly hydrophobic surface as the surface structure changes from polycrystalline grains to well-aligned nanorod arrays. This tunable growth of TiO(2) nanostructures is desirable for promising applications of TiO(2) nanostructures in the development of optical devices, sensors, photo-catalysts and self-cleaning coatings.

A novel nanostructure of a PtAu catalyst, alloyed PtAu nanodendrites, has been synthesized via a reproducible single-step hydrothermal co-reduction of Pt and Au inorganic precursors and shows exceptionally high catalytic activity towards the electrooxidation of formic acid.

No abstract

No abstract