Sep 4, 2012
Nanofibre-based gas sensors aid environmental monitoring
High-temperature electrochemical gas sensors can help to improve energy efficiency and reduce the emission of pollutants as part of feedback control systems in vehicles, coal-fired power plants, metal processing and glass manufacturing – to name just a few applications. The sensitivity of such sensors is highly dependent on the material composition and architecture of the sensing electrodes. These components require a large surface area, high porosity and fast electron transport, which makes one-dimensional nanomaterials ideal candidates. However, manufacturing challenges present a barrier to commercialization.
Recently, researchers in the US have explored the use of La0.8Sr0.2MnO3 nanofibres to tackle these issues. The group’s sensor electrode is constructed with numerous electrospun nanofibres with a diameter of around 200 nm as shown in the figure. Electrospinning is a simple and inexpensive technique for scaling up the manufacture of one-dimensional nanostructures.
Compared with conventional micron-sized powders, the nanofibres have a larger specific surface area and form a porous network that facilitates gas diffusion. In addition, the nanofibres are interconnected and form a continuous path for charge transport. The unique architecture increases the electrochemical reaction sites. As a result, the sensor exhibits enhanced sensitivity, lower detection limits and a faster response to the change in the gas concentration.
In the study, a sensor with a nanofibre-based electrode was used to successfully detect carbon monoxide at high temperature (>500 °C). This work demonstrates an effective route to improving the performance of high-temperature electrochemical sensors.
More details can be found in the journal Nanotechnology.
About the author
This study was performed by Dr Nianqiang (Nick) Wu and his group at West Virginia University in the US. More details on his research can be found by visiting his homepage.