Surface-Engineered 2D Nanomaterials in Gas Sensors: Advancement and Challenges.

Abstract

2D nanomaterials liketransition metal dichalcogenides (TMDs), MXene, nitrides, and black phosphorus-based gas sensors have garnered extensive attention in recentdecades. The extraordinary physicochemical and electrical properties of 2D nanomaterials make them highly sensitive toward gas molecules at roomtemperature. However, despite their potential, the current gas sensingtechnology suffers from inadequate selectivity, inaccurate detection and environmentalinstability. This review provides an overview of recent developments in surface-engineering routes to improve the sensing properties of 2D nanomaterials-based gas sensors. First, it covers emerging 2D nanomaterials, their synthesis routes, and gas-sensing mechanisms. Lateron, thoroughly explores renowned surface-engineering strategies such as defectmodulation, nanoparticle functionalization, and heteroatom doping to enhancethe gas sensing performance. Metal intercalation and partial surface oxidation/reductionapproaches are also discussed to tune the sensing characteristics. Furthermore, single-atom catalyst engineering highlights the anchoring of metalatoms on 2D nanomaterials to achieve enhanced atom utilization, leading tobetter catalytic sensing activities. The engineering techniques introduceeffective surface sensitization, modulated carrier concentration in 2D materials. This review outlines the key objectives of surface-engineeringstrategies to overcome the limitations of hybrid materials and pave the way fornext-generation sensors with enhanced sensing performance toimpact a wide range of applications.