Ammonia gas sensors based on chemically reduced graphene oxide sheets self-assembled on Au electrodes

Abstract

We present a useful ammonia gas sensor based on chemically reduced graphene oxide (rGO) sheets by self-assembly technique to create conductive networks between parallel Au electrodes. Negative graphene oxide (GO) sheets with large sizes (>10 μm) can be easily electrostatically attracted onto positive Au electrodes modified with cysteamine hydrochloride in aqueous solution. The assembled GO sheets on Au electrodes can be directly reduced into rGO sheets by hydrazine or pyrrole vapor and consequently provide the sensing devices based on self-assembled rGO sheets. Preliminary results, which have been presented on the detection of ammonia (NH3) gas using this facile and scalable fabrication method for practical devices, suggest that pyrrole-vapor-reduced rGO exhibits much better (more than 2.7 times with the concentration of NH3 at 50 ppm) response to NH3 than that of rGO reduced from hydrazine vapor. Furthermore, this novel gas sensor based on rGO reduced from pyrrole shows excellent responsive repeatability to NH3. Overall, the facile electrostatic self-assembly technique in aqueous solution facilitates device fabrication, the resultant self-assembled rGO-based sensing devices, with miniature, low-cost portable characteristics and outstanding sensing performances, which can ensure potential application in gas sensing fields.

Surface acoustic wave ammonia sensor based on ZnO/SiO2 composite film

“…According to Wang et al [9] revelation that in an air environment, oxygen molecules absorbed onto the surface of ZnO films to form O 2− , O − , O − 2 ions depending on the temperature by extracting electrons from the conduction band. This phenomenon would result in the formation of a depletion region at the surface.…”

“…Detection of NH 3 in trace amounts is important in terms of environmental protection and human health, as well as industry production. In recent years, numerous materials including semiconducting oxide materials, such as ZnO [1,2], ZrO 2 [3], CdO [4] and TiO 2 [5], organic compounds [6,7] and novel materials such as carbon nanotubes [8] and graphene [9,10] are exploited for ammonia detection due to their superior ammonia gas sensing properties. Composite system based sensors have been demonstrated good sensitivity and selectivity to a particular gas [11,12] by varying the type and composition of the components of the composite such as metal oxide-metal oxide [1,13], novel materials (carbon nanotube and graphene)-metal oxide [9,14], polymer-metal oxide [8,15] etc.…”

Sensitive detection of ammonia by reduced graphene oxide/polypyrrole nanocomposites

“…Patois et al [12] have studied ammonia gas sensing properties on microelectrode arrays of electrochemically deposited polypyrrole films. Ammonia gas sensing studies are also reported on rGO sensing devices, fabricated by self-assembled technique [13]. Graphenepolypyrrole composites prepared by oxidative polymerization technique are used for supercapacitor and Hg 2+ removal applications, respectively [14,15].…”

Dielectrophoretic assembly of Pt nanoparticle-reduced graphene oxide nanohybrid for highly-sensitive multiple gas sensor

“…A few-layered reduced graphene oxide (rGO) has recently been proposed as a promising gas sensing element owing to its controllable surface defect density. However, pristine rGO-based gas sensors exhibited relatively low sensitivity [13] or long recovery time [14,15], or required a complicated fabrication process [16].…”