Nanostructured Gas Sensors: From Air Quality and Environmental Monitoring to Healthcare and Medical Applications

Abstract

In the last decades, nanomaterials have emerged as multifunctional building blocks for the development of next generation sensing technologies for a wide range of industrial sectors including the food industry, environment monitoring, public security, and agricultural production. The use of advanced nanosensing technologies, particularly nanostructured metal-oxide gas sensors, is a promising technique for monitoring low concentrations of gases in complex gas mixtures. However, their poor conductivity and lack of selectivity at room temperature are key barriers to their practical implementation in real world applications. Here, we provide a review of the fundamental mechanisms that have been successfully implemented for reducing the operating temperature of nanostructured materials for low and room temperature gas sensing. The latest advances in the design of efficient architecture for the fabrication of highly performing nanostructured gas sensing technologies for environmental and health monitoring is reviewed in detail. This review is concluded by summarizing achievements and standing challenges with the aim to provide directions for future research in the design and development of low and room temperature nanostructured gas sensing technologies.

Recent Development of Hierarchical Metal Oxides Based Gas Sensors: From Gas Sensing Performance to Applications

“…[ 1–7 ] Among them, due to the close relationship with human health, the applications of gas sensors in indoor air quality monitoring, breath analysis, and food safety have received wide attentions. [ 8–10 ] Conventionally, several technologies can be used to detect gases, such as quartz crystal microbalance, surface acoustic wave, optical transducers, etc. [ 11–13 ] Nevertheless, these technologies often need bulky and expensive equipments or complex and professional operation process, and then are not suitable to be used in daily life.…”

One-Dimensional Metal Oxide Nanostructures for Chemical Sensors

“…Nanomaterials of all dimensionalities (0D, 1D, 2D, and 3D) and diversity of MOS such as TiO 2 , ZnO, SnO 2 , CuO, NiO and many others are being investigated for high-performance detection of gases, chemicals and biomolecules [14][15][16][17][18][19][20], mainly for applications in the fields of environmental monitoring, healthcare and health diagnostics [21,22]. Nanomaterials serve as building blocks for the assembly of nanostructured layers with high surface area and porosity, leading to more sensitive and faster chemical sensors.…”

Metal-Organic-Frameworks: Low Temperature Gas Sensing and Air Quality Monitoring

“…In recent decades, the rapid growth of urban populations has resulted in new public health concerns and environmental pollution [1,2], and the fast monitoring of air-and waterborne contaminants using effective sensors has grown considerably in importance [1,3]. An effective sensor should interact with the target analyte selectively with high sensitivity and short response time [2,[4][5][6]. In addition, the sensor should be cost-effective and demonstrate high reusability and reproducibility [2,7].…”

“…In addition, the sensor should be cost-effective and demonstrate high reusability and reproducibility [2,7]. Sensors can be utilized to detect pollutants/analytes in aqueous (such as heavy metals, toxic organic compounds, and antibiotics) and gaseous form (such as volatile organic compounds, toxic gases, and greenhouse gases) [2,6,8,9]. The latter has a wide range of applications in food quality processes, industrial gases detection, and disease diagnosis, as well as indoor air-quality monitoring [8,[10][11][12].…”

“…Generally, chemoresistive-based gas sensors provide a superior sensing response at room temperature compared to optical-based gas sensors. However, their slow response dynamic at low/room operating temperature and their lack of selectivity towards target gases hinder their real-world application [4][5][6].…”