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Ti3C2Tx MXene and its composites for toxic gas and humidity detection |
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| รหัสดีโอไอ | |
| Title | Ti3C2Tx MXene and its composites for toxic gas and humidity detection |
| Creator | Cao Thi Linh Chi |
| Contributor | Shu Han Hsu, Advisor |
| Publisher | Thammasat University |
| Publication Year | 2568 |
| Keyword | 2D-Ti3C2Tx sensing material, NH3 sensor, NO2 sensor, Self-powered humidity sensor |
| Abstract | The pursuit of precise sensing materials is crucial for advancing multi-gas detection technologies like electronic noses. This dissertation addresses this demand by exploring the enhanced sensing capabilities of titanium-based (Ti3C2Tx), MXene, a two-dimensional material renowned for its excellent electron conductivity, high surface area, and active terminal groups. Through targeted functionalization, composite formation, and structural modification, the sensitivity and stability of these sensors toward ammonia (NH3), nitrogen dioxide (NO2), and humidity are enhanced, proposing Ti3C2Tx as a potential material for achieving selective multi-analyte detection in real-world monitoring applications.To enhance NH3 adsorption, surface of pristine Ti3C2Tx was introduced with triethoxysilylpropyl succinic anhydride silane (TESPSA) and alternately coated with polyaniline (PANI), yielding COOH-Ti3C2Tx/PANI. This modification doubled the available carboxylic acid functionalization binding sites compared to pristine MXene OH-terminals, improving the binding strength compared to the OH- groups of pristine MXene. An optimized sensor prepared with five coating cycles showed the highest sensitivity, achieving a 214.7% resistance change at 80 ppm NH3, along with a faster response time than the pristine Ti3C2Tx/PANI sensor. While humidity impacted on the sensing performance, the COOH-Ti3C2Tx/PANI sensor still outperformed its pristine counterpart.To address the insensitivity of pristine Ti3C2Tx toward NO2, a good responsive and selective composite was developed using a facile sonication method. The composite of MXene and the metal oxide semiconductor MoO3 with a 1:1 mass ratio (1:1 MX/Mo sensor) was fabricated for low-concentration NO2 detection. The 1:1 MX/Mo sensor demonstrated excellent performance, showing a 24.56% gas response at 1 ppm NO2, which is 3.53 times higher than a pure MXene sensor. It can detect NO2 down to a very low concentration of 50−97 ppb at room temperature (25∘C) and exhibits wide-range detection (0.05 ppm to 10 ppm), high selectivity against common gases (NH3, CO, CO2, H2), and good stability. This sensor is promising for monitoring NO2 in ambient air or soil environments.Addressing the limitations of conventional, power-dependent humidity sensors, porous MXene (P-MX) films were fabricated and investigated for a self-powered humidity sensor using 1 M MgCl2 as a solid-state electrolyte. Porosity was controlled by adjusting the ratio of MXene and polylactide acid (PLA) spheres. The 12:8P-MX (volume ratio) sensor achieved a high output voltage of 0.83 V, a good sensitivity of 9.65 mV/%RH across an 11−97% RH range, and an ultra-fast response time of 3.86 s at 97% RH. Higher porosity was found to promote water molecule absorption and ion diffusion, leading to enhanced voltage output. The 12:8P-MX sensor was successfully applied in practical applications, including breath monitoring and indoor humidity detection.Through various modification and functionalization strategies-including surface functionalization for NH3, composite formation for NO2, and porous structure fabrication for humidity sensing-Ti3C2Tx has proven its ability in the sensing field. The developed sensors exhibited high sensitivity, good selectivity, and stability, demonstrating a practical methodology for fabricating high-performance gas and humidity sensors for real-life applications. |
