Novel gas sensors based on carbon nanotube networks

6 figures, 2 tables.-- Work presented at the 4th World Congress on biomimetics, artificial muscles and nano-bio, 6 - 9 November 2007, Torre Pacheco, Spain.Novel resistive gas sensors based on single-walled carbon nanotube (SWNT) networks as the active sensing element nave been investigated for gas detection. SWNTs networks were fabricated by airbrushing on alumina substrates. As-produced- and Pd-decorated SWNT materials were used as sensitive layers for the detection of NO2 and H2, respectively. The studied sensors provided good response to NO2 and H2 as well as excellent selectivities to interfering gases.This work has been supported by MEC (Spain, projects TEC2004-05098-C02-01/MIC and TEC2004-05098-C02-02/MIC, and Programa I3 2006 8 0I 060), and the European Regional Development Fund (ERDF)

Hydrogen sensors based on carbon nanotubes thin films

Single-walled carbon nanotubes (SWNTs) produced by arc-discharge have been researched as resistive gas sensors for H2 detection. Raw as well as modified single-walled carbon nanotubes were utilised as sensor material. Two types of modification treatments were carried out on the as grown SWNT material; chemical functionalization with palladium and doping with palladium by sputtering. CNTs were deposited on alumina substrates by airbrush. Two different alumina substrates (with and without heater element) were used to obtain the sensor devices. Conductance measurements were carried out in a N2 constant flow for H2 detection. The results demonstrate that the CNTs are p-type semiconductor materials, increasing their resistance with reducing gases. SWNTs functionalized with Pd show the best response when exposed to H2 at room temperature.This work has been supported by the project NANOENER MAT2002-04630-C02-01, Good-Food. IP, IST VI FM, and the CSIC Fuel Cell NetworkPeer reviewe

Enantioselective CuH-Catalyzed Anti-Markovnikov Hydroamination of 1,1-Disubstituted Alkenes

Enantioselective synthesis of β-chiral amines has been achieved via copper-catalyzed hydro­amination of 1,1-disubstituted alkenes with hydroxylamine esters in the presence of a hydrosilane. This mild process affords a range of structurally diverse β-chiral amines, including β-deuterated amines, in excellent yields with high enantio­selectivities. Furthermore, catalyst loading as low as 0.4 mol% could be employed to deliver product in undiminished yield and selectivity, demonstrating the practicality of this method for large-scale synthesis