Nanoparticles anchored strategy to develop 2D MoS₂ and MoSe₂ based room temperature chemiresistive gas sensors

The goal of current research in gas sensor technology is the development of a highly effective, small gas sensor that is able to operate at room temperature. There has been a surge in interest in 2D nanomaterials for the fabrication of high-performance gas sensor devices after graphene because of the exceptional physical, chemical, optical, and electrical properties of two-dimensional semiconductor nanomaterials. Among various 2D nanomaterials, we are focusing on transition metal dichalcogenides (TMDs) used for the fabrication of room temperature (RT) gas sensors because of their high surface area, large surface activity, extremely high carrier mobility, narrow bandgap, and high conductivity. Molybdenum disulfide (MoS₂) and molybdenum diselenide (MoSe₂), a well-researched TMDs, have drawn considerable attention across diverse domains for gas sensing materials at RT due to their intriguing two-dimensional layered structures and electrochemical features. The fabrication of chemiresistor sensors using MoS₂ and MoSe₂ has shown immense promise in meeting present-day demands, highlighting the remarkable technological advancements over the last several decades. It is anticipated that the strategic modification of the surface of MoS₂ and MoSe₂ nanomaterials using the decoration of nanoparticles will play a key role in the development of nanomaterials with unique chemical and physical properties as well as catalytic power, allowing them to boost the overall performance of gas sensors at RT. Herein, this review article provides an in-depth overview of the latest advancements made in MoS₂ and MoSe₂ nanomaterial-based chemiresistive gas sensors for the sensing of toxic gases at RT. Initially, we outline the method for synthesis and growth of MoS₂ and MoSe₂ nanomaterials, and the basic principles of sensing mechanisms are elucidated, relying on the charge transfer dynamics between gas species and MoS₂ and MoSe₂ nanomaterials. Furthermore, this article examines the current developments in the performance of gas sensors based on MoS₂ and MoSe₂ nanomaterials through the combination of nanocomposites, van der Waals heterostructures, doping, and decoration of nanoparticles, as well as their capabilities in sensing gases. Finally, this review offers insights into numerous emerging challenges and potential avenues for future research on gas sensor technologies utilising diverse 2D MoS₂ and MoSe₂ nanomaterials.