MXene nanomaterials have shown outstanding gas-sensing performance at room temperature because of their electrical conductivity and high-density surface functional groups. The sensing properties of MXenes are largely governed by surface adsorption and interlayer diffusion. In light of this sensing mechanism, surface alkalization and ion intercalation have been shown to enhance the gas-sensing performance of MXenes. However, a simple and reliable method for realizing this is still lacking. Here, we present an efficient method to enhance the sensing performance of Ti3C2Tx MXene sensors while retaining their native uniform laminate structure. We show that by adding a controlled amount of alkaline ionic additives, the density of hydroxyl surface groups and intercalated metal ions can be increased inside the thin film structure, which cannot be achieved using acidic or neutral ionic additives with similar elemental compositions. In terms of a signal-to-noise ratio (SNR), Ti3C2Tx mixed with potassium hydroxide was 20 times more sensitive than pristine Ti3C2Tx toward ethanol vapor, thus demonstrating its high sensitivity. In addition, a very high SNR of 700 was achieved toward 100 ppm ammonia gas, which is one of the highest ever reported.
Bibliographical noteFunding Information:
This research was supported by a National Research Foundation of Korea (NRF) grant (2021R1C1C1006385, 2021M3H4A1A03047327) funded by the Ministry of Science and ICT (MSIT). This research was also supported by the National Research Council of Science & Technology (NST) grant by the Korea government (MSIT) (CRC22031-000), the Technology Innovation Program (00144157, Development of Heterogeneous Multi-Sensor Micro-System Platform) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea), and by KIST internal research programs funded by the Korea Institute of Science and Technology (KIST).
© 2022 American Chemical Society.
- gas sensor
- high sensitivity
- ionic additive
ASJC Scopus subject areas
- Materials Science(all)