modification on the surface of Ti3C2Tx.49 In terms of NH3sensing, the adsorption of NH3 molecules was investigated bythe researchers32,33 on the basis of the first principlecalculation. In route 2 of Figure 8, the N atom in the NH3molecule was adsorbed on the top of the Ti atom in theTi3C2Tx. A strong bond was also formed between the N and Tiatoms. However, Ti atom-adsorbed NH3 was slightly hauledout with a stretched Ti−C bond. The reversible interactionbetween them contributed to the high adsorption capacity.Additional -O terminals brought by the alkaline treatmentresulted in the increase of the N−Ti bonding site, which couldcause the increase of NH3 adsorption. Previous researchindicated that the rise of resistance is due to Ti3C2Txtransforming into a semiconductor after oxygen functionalization, which is an advantage to the enhancement of gas- andhumidity-sensing properties.27 The response signal of alkalizedTi3C2Tx exhibited a negative variation, which was alsoobserved in the humidity-sensing measurement. The shift indirection of the response signal was due to the carrier type ofTi3C2Tx changing after oxygen functionalization.50 Accordingly, Ti3C2Tx has considerable NH3- and humidity-sensingproperties after the alkaline treatment. Moreover, Ti3C2Tx is apotential candidate for NH3 and humidity sensors.