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 (Ti₃C₂T_x MXene) modified by vanadium pentoxide nanoparticle (V₂O₅) 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 V₂O₅ is 25%, V₂O₅ 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/V₂O₅ composites sensor has a good response (12.12) to 10 ppm NH₃. The enhanced sensing performance can be attributed to the modification of V₂O₅ nanoparticles as well as the catalytic effect and the formation of heterojunction. The doped V₂O₅ nanoparticles open up the unstratified portion of MXene and catalyze the chemisorption of oxygen and oxidation of NH₃. The difference in Fermi level between two-dimensional MXene and V₂O₅ drives the charge transfer at the heterojunction interface, enriching the electrons on the surface of V₂O₅, thus improving the sensitivity. Density functional theory suggests that the composite adsorption system is more stable and has lower NH₃ adsorption energy. This work provides a feasible route to develop high-performance gas sensors with MXene-based composites.