Enhanced Room-Temperature NO 2 Sensing through Deep Functional Group Hybridization in Nitrogen-Doped Monolayer Ti 3 C 2 T x .

Nitrogen dioxide (NO 2 ) is a significant environmental and human health hazard. Current NO 2 sensors often lack sensitivity and selectivity under ambient conditions. This study investigates ammonia pyrolysis modification of monolayer Ti 3 C 2 T x MXene to enhance NO 2 detection at room temperature. Nitrogen-doped Ti 3 C 2 T x demonstrates a substantial improvement in sensitivity, with a response of 8.87% to 50 ppm of NO 2 compared to 0.65% for the original sensor, representing a 13.8-fold increase. The nitrogen-doped sensor also exhibits superior selectivity and linearity for NO 2 under ambient conditions. Theoretical analysis shows that nitrogen incorporation promotes enhanced interaction between Ti 3 C 2 T x and its surface oxygen-containing functional groups through electronic hybridization, resulting in improved adsorption energy (1.80 |eV|) and electron transfer efficiency (0.67 |e|) for NO 2 , thereby enhancing its gas-sensing performance. This study highlights the potential of ammonia pyrolysis-treated Ti 3 C 2 T x MXene for advancing NO 2 sensor technologies with heightened performance at room temperature.