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Highly Sensitive and Selective Hydrophilic and Hydrophobic Graphene Oxide Gas Sensor

Technology Overview

Volatile organic compounds (VOCs) are organic compounds that easily vaporises. Along with carbon, they contain elements such as hydrogen, oxygen, fluorine, chlorine, bromine, sulphur or nitrogen. Many VOCs are hazardous air pollutants, and are health and environmental risks.

A method detecting such gases is through the use of optical sensors, which has several advantages over electronic sensors such as being electromagnetically unsusceptible. 1-dimensional semiconducting metal oxide nanowires have been widely investigated due to their high sensitivity to different compounds, but they are often bogged down by humidity interference, hence requiring operating temperatures above 100oC. Several further studies have shown that hydrophobic, 2-dimensional (2D) reduced Graphene Oxide (rGO) is able to overcome this problem and functions with high sensitivity in high humidity environments, allowing for low temperature use.

In this technology, a novel hydrophilic, 2D Graphene Oxide (GO) based gas sensor, was developed. The GO sensor is able to maintain high sensitivity in highly unfavourable conditions (up to 90% relative humidity, strongly acidic or basic) and outperforms the rGO. This technology also proposes the combined use of rGO and GO in a gas sensor, to provide the ability for distinguishing between tetrahydrofuran (THF) and dichloromethane (MC), in addition to the above benefits.

Technology Features & Specifications

This technology features:

  • A highly sensitive and selective gas sensor made from Graphene Oxide (GO) and reduced GO (rGO)
  • A sensor that maintains high sensitivity and selectivity under unfavourable conditions such as high humidity, strongly acidic and basic environments
  • A method of fabricating a gas sensor or a gas sensor array consisting of optical fibre(s) with a coating layer of GO, rGO and a combination of both GO and rGO

Potential Applications

The technology can be applied, but not limited to the following:

  • Gas and particle control sensor
  • Monitoring of environmental pollution
  • Chemical component analysis
  • In environments with high humidity (up to 90% RH)
  • In strongly basic and acidic conditions
  • Monitoring of compounds consisting of COx, NOx, NH3, LPG, H2S, benzene, toluene etc.

Customer Benefits

  • Improved sensitivity/detection limit – ability to detect low concentrations of VOCs, from 500 ppm to 500 ppb, depending on the compound
  • Maintains a higher sensitivity/detection limits under high humidity conditions of up to 90% RH
  • Increased sensitivity of VOCs under strongly basic (pH 2 or less) and acidic condition (pH 10 or more) due to characteristics of rGO and GO
  • Fast signal recovery to baseline of GO sensor compared to rGO sensors

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