Advances of Nano-Enabled ZnFe2O4 Based-Gas Sensors for VOC Detection and Their Potential Applications: A Review

The demand for reliable gas sensing technologies in chemical, manufacturing, environmental, and occupational sites has increased in the last few decades following the global volatile gas sensor market, which is expected to grow further beyond 2025. Currently, several types of sensors have been employed for applications in different fields. Optical sensors are widely implemented in mining and environmental monitoring. Conventional food testing methods are utilized for the detection of any chemical or microbial agent in the food industry. Although robust and sensitive, most sensing technologies are expensive, labor-intensive, and necessitate the use of time-consuming gas sampling pretreatment steps, and these issues impede the achievement of quick, simple detection, portable, and cost-effective gas monitoring. For this reason, researchers around the world are investigating the possibility of using gas sensors as a promising technology that has the potential to alleviate industrial safety concerns. As a highly sensitive semiconducting metal oxide, gas sensors based on ZnFe2O4 have the potential to ensure environmental and occupational safety in real time. This review introduces and highlights recent developments in ZnFe2O4 gas sensors for application in different fields. The challenges limiting the wide application of the ZnFe2O4 sensor are outlined. Furthermore, this review discusses the common strategies adopted to improve the sensing properties of ZnFe2O4 for gas detection. Finally, future perspectives on further improvements of ZnFe2O4 sensing properties are discussed, and integration of ZnFe2O4 sensors into electronic noses to tackle the selectivity issue and how they can feature on the Internet of Things is outlined.