Gas Sensing with Au-Decorated Carbon Nanotubes

Abstract

The sensing properties of carbon nanotubes (CNTs) decorated with gold nanoparticles have been investigated by means of combined theoretical and experimental approaches. On one hand, first-principles and nonequilibrium Green's functions techniques give access to the microscopic features of the sensing mechanisms in individual nanotubes, such as electronic charge transfers and quantum conductances. On the other hand, drop coating deposition of carbon nanotubes decorated with gold nanoparticles onto sensor substrates and their characterization in the detection of pollutants such as NO(2), CO, and C(6)H(6) provide insight into the sensing ability of nanotube mats. Using the present combined approaches, the improvement in the detection of some specific gases (NO(2) and CO) using Au-functionalized nanotubes is explained. However, for other gases such as C(6)H(6), the Au nanoparticles do not seem to play a crucial role in the sensing process when compared with pristine CNTs functionalized with oxygen plasma. Indeed, these different situations can be explained by identifying the relationship between the change of resistance (macroscopic feature) and the shift of the Fermi level (microscopic feature) after gas adsorption. The understanding of the sensing ability at the atomic level opens the way to design new gas sensors and to tune their selectivity by predicting the nature of the metal that is the most appropriate to detect specific molecular species.

Bio‐Inspired Carbon Monoxide Sensors with Voltage‐Activated Sensitivity

“…[46][47][48] This approach is similar to that used by Zanolli et al who used the computed location of the Fermi level to illuminate the sensing behaviors of a gold-decorated SWCNT. [46] The ground-state geometries, computed distance between the SWCNT and Fe, the bond lengths between Fe and the ligands, binding angles between Fe and the ligands, and the charge transfer between SWCNT and porphyrin are shown in Figure S10 and Table S4. Figure 6 shows the change in computed Fermi energy (ΔE f ) upon adsorption of Fe II porphyrin to a (5,5) SWCNT fragment and the subsequent binding of CO or O 2 .…”

Pt- and Ag-Decorated Carbon Nanotube Network Layers for Enhanced NH₃ Gas Sensitivity at Room Temperature

“…However, the response of pristine CNTs to gases is weak and scarcely selective because of the low chemical reactivity of CNTs with the molecular environment. 8) Noble metal-decorated CNTs are expected to be a new type of sensing material with high sensitivity and excellent selectivity. 913) In this paper, multi-walled CNTs were grown on alumina substrate patterned with Pt electrodes by CVD method and functionalized with Ag and Pt with 2 and 4 nm nominal thicknesses.…”

A rapid and automated relocation method of an AFM probe for high-resolution imaging

“…Owing to their excellent electrical, chemical, and physical properties, Au-CNT composite materials [37,38] possess broad application prospects in fuel cells, catalysts, nanoelectronic devices, sensors, etc [39,40]. During the experimental process of tracking detection for CNTs, we characterized the variations of the morphology structure and electrical properties of the same CNTs with Au coatings of different thicknesses by using AFM.…”