Highly sensitive and selective trimethylamine sensor using one-dimensional ZnO-Cr2O3 hetero-nanostructures.

Nanotechnology (2012-05-30)
Hyung-Sik Woo, Chan Woong Na, Il-Doo Kim, Jong-Heun Lee
RESUMEN

Highly selective and sensitive detection of trimethylamine (TMA) was achieved by the decoration of discrete p-type Cr(2)O(3) nanoparticles on n-type ZnO nanowire (NW) networks. Semielliptical Cr(2)O(3) nanoparticles with lateral widths of 3-8 nm were deposited on ZnO NWs by the thermal evaporation of CrCl(2) at 630 °C, while a continuous Cr(2)O(3) shell layer with a thickness of 30-40 nm was uniformly coated on ZnO NWs at 670 °C. The response (R(a)/R(g): R(a), resistance in air; R(g), resistance in gas) to 5 ppm TMA of Cr(2)O(3)-decorated ZnO NWs was 17.8 at 400 °C, which was 2.4 times higher than that to 5 ppm C(2)H(5)OH and 4.3-8.4 times higher than those to 5 ppm p-xylene, NH(3), benzene, C(3)H(8), toluene, CO, and H(2). In contrast, both pristine ZnO and ZnO (core)-Cr(2)O(3) (shell) nanocables (NCs) showed comparable responses to the different gases. The highly selective and sensitive detection of TMA that was achieved by the deposition of semielliptical Cr(2)O(3) nanoparticles on ZnO NW networks was explained by the catalytic effect of Cr(2)O(3) and the extension of the electron depletion layer via the formation of p-n junctions.

MATERIALES
Referencia del producto
Marca
Descripción del producto

Sigma-Aldrich
Trimethylamine solution, 43.0-49.0% in H2O (T)
Sigma-Aldrich
Trimethylamine, anhydrous, ≥99%
Sigma-Aldrich
Trimethylamine hydrochloride, 98%
Sigma-Aldrich
Chromium(III) oxide, powder, 99.9% trace metals basis
Sigma-Aldrich
Chromium(III) oxide, powder, ≥98%
Sigma-Aldrich
Trimethylamine solution, 31-35 wt. % in ethanol, 4.2 M, contains toluene as stabilizer
Sigma-Aldrich
Trimethylamine solution, 25 wt. % in H2O
Sigma-Aldrich
Chromium(III) oxide, nanopowder, <100 nm particle size (TEM), 98% trace metals basis
Sigma-Aldrich
Trimethylamine solution, 25 wt. % in propylene glycol