Development of Highly Sensitive and Humidity Independent Room Temeprature NO₂ Gas Sensor Using Two Dimensional Ti₃C₂T_x Nanosheets and One Dimensional WO₃ Nanorods Nanocomposite

Abstract

Room temperature gas sensors have been widely explored in gas sensor technology for real-time applications. However, humidity has found to affect the room temperature sensing and the sensor life, necessitating the development of novel sensing materials with high sensitivity and stability under humid conditions at room temperature. In this work, the room temperature sensing performance of a Ti 3 C 2 T x decorated, WO 3 nanorods based nanocomposite has been investigated. The hydrothermally synthesized WO 3 / Ti 3 C 2 T x nanocomposite has been investigated for structural, morphological, and electrical studies using X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and Brunanuer−Emmett− Teller techniques. The WO 3 /Ti 3 C 2 T x sensors have been found to be highly selective to NO 2 at room temperature and exhibit much higher sensitivity in comparison to pristine WO 3 nanorods. Furthermore, sodium L-ascorbate treated Ti 3 C 2 T x sheets in WO 3 /Ti 3 C 2 T x enhanced the stability and reversibility of the sensor toward NO 2 even under variable humidity conditions (0−99% relative humidity). This study shows the potential room temperature sensing application of a WO 3 / Ti 3 C 2 T x nanocomposite-based sensor for detecting NO 2 at sub-ppb level. Further, a plausible sensing mechanism based on WO 3 / Ti 3 C 2 T x nanocomposite has been proposed to explain the improved sensing characteristics.

Self-Powered Wearable Gas Sensors Based on l-Ascorbate-Treated MXene Nanosheets and SnO2 Nanofibers

“…To address this challenge, the sodium L-ascorbate antioxidant treatment of MXene with highly stable semiconductor metal oxides (SMOs), widely used SnO 2 , has been reported restricting the humidity degradation and enhances the stability of the sensor by doing interfacial engineering. 4 The interfacial engineering led to the formation of heterojunctions that increases the specific surface area resulting in improved gas adsorption and transduction function for gas sensors 20 and has been reported for the SnO 2 −TiO 2 − Ti 3 C 2 T x sensor, where 18 and 2.5 times higher sensitivity is observed toward NO 2 in comparison to Ti 3 C 2 T x and TiO 2 − Ti 3 C 2 T x , respectively. 21 Similarly, the W 18 O 49 /Ti 3 C 2 T X composite-based sensor exhibit a high response of 11.6 toward 20 ppm acetone at RT.…”

“…With the growing trends in wearable remote gas sensing, the gas sensors have become increasingly important in a variety of fields such as medical health, air quality monitoring, and industrial manufacturing. Materials used to fabricate these wearable gas sensors should exhibit a combination of gas sensing features, including high receptor function, transducer function, utility factor, low fabrication cost, low power consumption, and room temperature (RT) sensing capable of monitoring a variety of toxic gases including volatile organic compounds (VOCs), CO, H 2 S, NO X , SO 2 , and so forth. − Apart from the choice of sensing materials, the power sources required to operate these gas sensors increase their assembly cost and limit their wearability. In view to this, the development of a highly sensitive RT self-powered gas sensor that can scavenge energy from human motion, wind, and vibrations without an external power source is of paramount importance for future smart sensor applications.…”

“…Despite excellent sensing characteristics, the oxidation degradation of MXene under a humid environment severely affects its surface area and electrical properties which results in poor long-term stability toward gas sensors. To address this challenge, the sodium l -ascorbate antioxidant treatment of MXene with highly stable semiconductor metal oxides (SMOs), widely used SnO 2 , has been reported restricting the humidity degradation and enhances the stability of the sensor by doing interfacial engineering . The interfacial engineering led to the formation of heterojunctions that increases the specific surface area resulting in improved gas adsorption and transduction function for gas sensors and has been reported for the SnO 2 –TiO 2 –Ti 3 C 2 T x sensor, where 18 and 2.5 times higher sensitivity is observed toward NO 2 in comparison to Ti 3 C 2 T x and TiO 2 –Ti 3 C 2 T x , respectively .…”

Edge-Site-Enriched Ti3C2Tx MXene/MoS2 Nanosheet Heterostructures for Self-Powered Breath and Environmental Monitoring

“…The construction of MXene heterostructures with semiconductor metal oxides is one of the promising strategies to resolve these issues by rectifying the electrical properties through the synergistic effects of components. Several studies, such as MXene/SnO 2 , 18 MXene/TiO 2 , 19 MXene/WO 3 , 20,21 MXene/Co 3 O 4 , 22 and so forth, have confirmed the heterogeneous effects on the improvement of gas sensing performance. However, the reports on transition-metal dichalcogenides (TMDs)/MXene heterostructures are limited, while their optimal interface modulation along with the synergistic structural effects may supplement the effective adsorption of target analytes on the resulting surface if the components are systematically engineered.…”

Synergistic Effect of TiS3 and Ti3C2Tx MXene for Temperature-Tunable p-/n-Type Gas Sensing

“…This observation is consistent with the previously reported stability of the room-temperature sensor response of another MXene composite sensor based on Ti 3 C 2 T x -WO 3 . 25 When the device was finally purged with dry nitrogen, the background resistance slowly decreased toward the original levels (Figure 2c).…”