MXene Composite-Based Sensor for Environmental Monitoring

Environmental monitoring has seen a substantial transformation due to the quick development of nanotechnology, particularly with the introduction of MXene-based composites as high-performance sensor materials. MXenes are a family of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides with remarkable qualities such as a vast surface area, excellent electrical conductivity, chemical adaptability, and customizable surface terminations. However, problems including restacking, chemical instability, and lack of selectivity frequently restrict their usefulness as sensors. MXene composites, which are created by integrating metal nanoparticles, carbon nanostructures, polymers, or metal-organic frameworks (MOFs), have been developed to improve sensitivity, selectivity, and long-term stability to overcome these difficulties. MXene composite-based sensors for environmental pollutant detection are thoroughly reviewed in this chapter, including synthesis techniques, fabrication methods, sensing mechanisms (electrochemical, resistive, capacitive, and optical), and real-world applications in soil, water, and air matrices. Significant examples include the detection of pesticides (like atrazine and carbendazim), heavy metals (like Pb 2+ and Hg 2+ ), phenolic chemicals (like bisphenol-A and 4-nitrophenol), and hazardous gases (like NH 3 and CO 2 ). Many systems exhibit detection limits in the nanomolar to picomolar range. Recent developments in integrated, flexible, and small microfluidic sensor platforms are also covered. This chapter ends with a critical analysis of existing constraints, such as repeatability and oxidation stability, and suggests potential paths for real-time, field-deployable environmental monitoring, such as surface functionalization, device integration, and sustainable synthesis.