Revolutionizing Greenhouse Gas Monitoring with Layered MXenes: Room-Temperature Chemoresistors

Greenhouse gas (GHG) emissions, particularly carbon dioxide, methane, and nitrous oxide, are the primary cause of global warming and climate change. To effectively monitor the actual impact of emission of these gases, specialized gas measurement systems that are specifically adapted are necessary. Currently, National surveillance agencies rely on highly sensitive, selective, complex, bulky, and expensive systems to monitor the environment. These systems serve as reference units and are only installed in a few specific, mostly fixed, key locations. However, in order to achieve a more comprehensive monitoring approach and develop climate change models, it is essential to have a distributed network of sensing system. This can be achieved through the deployment and connection of numerous gas sensing systems enabled by the Internet of Things (IoT). These devices need to be sensitive, selective, and energy-efficient, although they may have lower accuracy and precision compared to the reference instruments. Existing commercial sensors do not meet all the necessary requirements, highlighting the need for new and enhanced functional nanomaterials and sensors.<br/>The objective of this research is to demonstrate the current state of development regarding advanced miniaturized gas sensing devices for monitoring GHG emissions. For this, we have developed a chemiresistive sensor platform that utilizes a layered structure of 2D MXenes, serving as an advanced sensing platform for detecting GHGs. The layered MXenes were synthesized using a chemical etching method involving a strong HF etchant, resulting in the formation of multilayered Ti3C2TX (MXene) sheets. These MXene sheets were then integrated onto a chip with interdigitated electrodes to form a microsensor. In this way, a low-cost gas-sensitive sensor for methane (CH4) was developed, which exhibited superior selectivity in front of other gases.<br/>Throughout this research, a comprehensive investigation of the synthesis and of greenhouse gas detection application of these 2D MXenes has been conducted. This study is expected to pave the way for the utilization of a broad range of MXenes as highly sensitive sensors for greenhouse gases.