This study employs first-principles calculations to investigate functionalized ${\mathrm{Mo}}_2\mathrm{N}{T}_2$ (T = Ø, $\mathrm{H}$, $\mathrm{O}$, $\mathrm{F}$) MXenes as dual-functional materials for toxic gas capture and sensing applications. The surface of the pristine ${\mathrm{Mo}}_2\mathrm{N}$ surface is unsaturated, possesses dangling bonds, and exhibits a strong capability to capture various environmental gases. Surface functionalization significantly modulates this behavior: ${\mathrm{Mo}}_2{\mathrm{NH}}_2$ demonstrates remarkable selectivity toward ${\mathrm{NO}}_x$ capture, while ${\mathrm{Mo}}_2{\mathrm{NO}}_2$ emerges as a superior $\mathrm{NO}$ sensor due to its optimal adsorption strength (−0.342 eV), substantial charge transfer (−0.197 e), and 14%–18% current reduction in nanodevice measurements. Notably, investigations of mixed-terminated ${\mathrm{Mo}}_2{\mathrm{NO}}_x(\mathrm{OH})y$ systems reveal that hydroxyl concentration dictates $\mathrm{NO}$ reaction pathways: low $\mathrm{OH}$ triggers proton abstraction, forming $\mathrm{O}$-$\mathrm{N}$-$\mathrm{H}$ structures, whereas high $\mathrm{OH}$ induces direct $\mathrm{O}\text{−}\mathrm{H}$ cleavage, generating ${\mathrm{H}}_2\mathrm{N}\text{−}\mathrm{OH}$. Although water passivation mitigates these reactions, irreversible chemical transformations persist, underscoring that precise control of surface chemistry, particularly terminal-group engineering, is essential for achieving the selective capture capabilities and reversible sensing performance required for next-generation MXene-based gas management platforms.

Close

PrevNext

View figure in article

• Adsorption
• Chemical Physics & Physical Chemistry
• Density of states
• Electronic structure
• 2-dimensional systems
• Functional materials
• Solid-state detectors
• Density functional calculations