Unexpected Performance Improvements of Nitrogen Dioxide and Ozone Sensors by Including Carbon Monoxide Sensor Signal

Recent trends in ozone sensing technology

The harmful impact of ozone on humans and the environment makes the development of economical, accurate, and efficient ozone monitoring technologies necessary. Therefore, in the present review, we critically discuss developments in the methods for the synthesis of ozone sensing materials such as metal oxides (Ni, Co, Pd, In, Cu, Zn, Fe, Sn, W, Ti and Mo), carbon nanotubes, organic compounds, perovskites, and quartz. Additionally, the recent advancements and innovations in ozone technology will be discussed. In this review, we focus on assembling ozone-sensing devices and developing related wireless communication, data transferring, and analyzing technologies together with satellite, airborne, and ground-based novel ozone-sensing strategies for monitoring the atmosphere, urban areas, and working environments. Furthermore, the developments in ozone-monitoring miniaturized devices technology will be considered. The effects of different factors, such as spatial-temporal variation, humidity, and calibration, on ozone measurements will also be discussed. It is anticipated that this review will bridge the knowledge gaps among materials chemists, engineers, and industry.

Chemiresistors with In2O3 Nanostructured Sensitive Films Used for Ozone Detection at Room Temperature

Detection of greenhouse gases is essential because harmful gases in the air diffuse rapidly over large areas in a short period of time, causing air pollution that will induce climate change with catastrophic consequences over time. Among the materials with favorable morphologies for gas detection (nanofibers, nanorods, nanosheets), large specific surfaces, high sensitivity and low production costs, we chose nanostructured porous films of In₂O₃ obtained by the sol-gel method, deposited on alumina transducers, with gold (Au) interdigitated electrodes (IDE) and platinum (Pt) heating circuits. Sensitive films contained 10 deposited layers, involving intermediate and final thermal treatments to stabilize the sensitive film. The fabricated sensor was characterized using AFM, SEM, EDX and XRD. The film morphology is complex, containing fibrillar formations and some quasi-spherical conglomerates. The deposited sensitive films are rough, thus favoring gas adsorption. Ozone sensing tests were performed at different temperatures. The highest response of the ozone sensor was recorded at room temperature, considered to be the working temperature for this specific sensor.