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Sensing Properties (sensing + property)
Selected AbstractsDirect Conversion of Single-Layer SnO Nanoplates to Multi-Layer SnO2 Nanoplates with Enhanced Ethanol Sensing PropertiesADVANCED FUNCTIONAL MATERIALS, Issue 15 2009Kun-Mu Li Abstract Direct conversion of single-layer SnO nanoplates to multi-layer SnO2 nanoplates is achieved by annealing in an O2 ambient at 700,°C. For 50,ppm ethanol, the sensitivities of the multi-layer SnO2 nanoplates are more than double that of single-layer SnO2 nanoplates, which are also formed from the single-layer SnO. The higher sensitivity of the multi-layer nanoplates is attributed to their larger surface/volume ratio. The facile fabrication of interconnected multi-layer SnO2 nanoplates at low temperature directly on a Si substrate and sensing chip without the aid of catalysts offers vast advantages over competing methods for the fabrication of high-sensitivity SnO2 sensors. [source] ,-Fe2O3 Nanorings Prepared by a Microwave-Assisted Hydrothermal Process and Their Sensing Properties,ADVANCED MATERIALS, Issue 17 2007X. Hu Free-standing , -Fe2O3nanorings are synthesized in solution through a rapid microwave-assisted hydrothermal process. The ringlike structure is a new member in the family of iron oxide nanostructures. The sensors made of the ,-Fe2O3 nanorings exhibit high sensitivity not only for bio-sensing of hydrogen peroxide in a physiological solution but also for gas-sensing of alcohol vapor at room temperature. [source] New Polyalkynyl Dendrons and Dendrimers: "Click" Chemistry with Azidomethylferrocene and Specific Anion and Cation Electrochemical Sensing Properties of the 1,2,3-Triazole-Containing DendrimersCHEMISTRY - A EUROPEAN JOURNAL, Issue 12 2009Jérémy Camponovo Abstract Dendrimers for ion sensing: The synthesis and use of new tris-alkynyl dendrons are reported. So-called "click" reactions of the dendrimers described with azidomethylferrocene give 27-ferrocenyl, 81-ferrocenyl, and 243-ferrocenyl dendrimers. Electrochemical recognition of oxo-anions and Pd2+ cations has been compared using the three polyferrocenyl dendrimers. The synthesis and use of the new tris-alkynyl dendrons 2 to 5 are reported, including the Williamson reaction of 5 with 9-iodo (9), 27-iodo (11), and 81-iodo (12) dendritic cores to yield 27-alkynyl (13), 81-alkynyl (14), and 243-alkynyl (15) dendrimers. So-called "click" reactions of these three dendrimers with azidomethylferrocene (20) give 27-ferrocenyl (16), 81-ferrocenyl (17), and 243-ferrocenyl (18) dendrimers. Electrochemical recognition of oxo-anions (H2PO4, and ATP2,) and Pd2+ cation has been compared using the three polyferrocenyl dendrimers. Derivatization of Pt electrodes with the dendrimers for recognition becomes more facile with increasing size of the dendrimer. This first "click" dendrimer bearing 243-ferrocenyl groups is the best one in the series to obtain robust, recyclable modified Pt electrodes, whereas previous "click" ferrocenyl dendrimers have not been suitable for this purpose. Nous reportons ici la synthèse et l'utilisation de nouveaux dendrons tris-alcynes (composés 2 à 5). La réaction de Williamson entre 5 et les c,urs dendritiques polyiodés comportant 9, 27 ou 81 branches (composés 9, 11 et 12) conduit aux dendrimères poly-alcynes à 27, 81 et 243 branches respectivement (composés 13 à 15). La réaction "click" de ces dendrimères avec l'azidométhylferrocène (20) permet d'obtenir des dendrimères polyferrocéniques à 27, 81 et 243 branches (composés 16 à 18). La reconnaissance électrochimique d'oxo-anions (H2PO4,et ATP2,) et du cation Pd2+est comparée avec trois dendrimères polyferrocéniques, et l'obtention d'électrodes de Pt modifiées à l'aide de ces dendrimères pour cette reconnaissance est de plus en plus facile lorsque la taille du dendrimère augmente. Le premier dendrimère "click" comportant 243 ferrocènes est le meilleur de la série pour la modification d'électrodes de Pt. Ces électrodes sont robustes et recyclables avec ce dendrimère, alors que les dendrimères "click" précédemment publiés n'étaient pas utilisables pour cette fonction. [source] Facile Fabrication of Pure ,-Fe2O3 Nanoparticles via Forced Hydrolysis Using Microwave-Assisted Esterification and their Sensing PropertyJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2009Yafeng Li In this paper we firstly demonstrate a facile approach for the rapid fabrication of ,-Fe2O3 using microwave-assisted esterification. In situ -generated water leads to the forced hydrolysis of Fe3+. Microwave irradiation greatly promotes the growth of ,-Fe2O3 nanoparticles compared with conventional solvothermal approach, and agitation can assure the obtainment of pure hematite phase. The akaganeite phase is preserved without stirring. The BET specific surface area reaches 83 m2/g although high concentration of FeCl3 is adopted. Our approach can assure the very rapid acquisition of hematite nanoparticles. Electrochemical studies indicate that our product can function as a candidate for high-performance sensor. [source] Preparation of Nanogapped Gold Nanoparticle Array for DNA DetectionELECTROANALYSIS, Issue 4 2008Shiho Tokonami Abstract A novel DNA detection technique using a gold nanoparticle array film electrode has been reported here. The gold nanoparticles molecularly linked with binder molecule (1,10-decanedithiol) were separated 1.3,nm from each other, and the DNA conductivity change from single to double strand was measured by monitoring a voltage drop across the particles, between which a probe of a 12-mer oligonucleotide was immobilized. In adding a complementary oligonucleotide on the nanoparticle film chip, an immediate decrease in the film resistance (ca. 1.4 ,) due to a hybridization event occurred in a reproducible manner with this simple setup. In the paper, we have an interest in the primary sensing properties; effect of the film resistance on the sensor response, dependence of the resistance change on the DNA concentration, and the performance of the system for DNA detection including single nucleotide polymorphisms were described. [source] A Rapidly Responding Sensor for Methanol Based on Electrospun In2O3,SnO2 NanofibersJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2010Wei Zheng In this paper, we presented a simple and effective electrospinning technique for the preparation of In2O3,SnO2 composite nanofibers. The morphology and chemical structure of the as-prepared samples were analyzed by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results showed that large quantities of In2O3,SnO2 composite nanofibers with diameters from 60 to 100 nm were obtained. The In2O3,SnO2 composite nanofibers exhibited excellent gas sensing properties to methanol, such as fast response/recovery properties, high sensitivity, and good selectivity. [source] | |||||||||||||