Layered Ti3C2Tx MXene heterostructured with V2O5 nanoparticles for enhanced room temperature ammonia sensing

To enhance ammonia sensing at room temperature (25°C), Two-dimensional transition metal carbonyl nitride (Ti ₃C ₂T _x MXene) modified by vanadium pentoxide nanoparticle (V ₂O ₅) is synthesized by hydrothermal method. The effects of weight ratio on the microstructure and ammonia sensing performance at room temperature are studied. The results indicate that when the weight percentage of V ₂O ₅ is 25 %, V ₂O ₅ nanoparticles with an average size of 90.33 nm are produced on the surface and between the layers of the two-dimensional MXene. The prepared MXene/V ₂O ₅ composites sensor has a good response (12.12) to 10 ppm NH ₃. The enhanced sensing performance can be attributed to the modification of V ₂O ₅ nanoparticles as well as the catalytic effect and the formation of heterojunction. The doped V ₂O ₅ nanoparticles open up the unstratified portion of MXene and catalyze the chemisorption of oxygen and oxidation of NH ₃. The difference in Fermi level between two-dimensional MXene and V ₂O ₅ drives the charge transfer at the heterojunction interface, enriching the electrons on the surface of V ₂O ₅, thus improving the sensitivity. Density functional theory suggests that the composite adsorption system is more stable and has lower NH ₃ adsorption energy. This work provides a feasible route to develop high-performance gas sensors with MXene-based composites.