Highly stable, fast responsive Mo2CTx MXene sensors for room temperature carbon dioxide detection

Abstract

MXenes are the emerging class of 2D materials with numerous applications such as in energy storage, biomedical, catalysis, gas sensing, etc. Among these, the gas sensing application of MXene materials is gaining attention due to their higher sensitivity towards various gases but is least explored. Herein we report the fabrication of highly sensitive CO 2 gas sensors using a porous silicon/Mo 2 CT x hybrid system. The structure of the Mo–In–C non-MAX phase and formation of Mo 2 CT x MXene were studied using X-ray diffraction. The elemental characterization through XPS and EDS confirms the presence of the functional groups and the deposition of the Mo 2 CT x MXene films. The uniform deposition of the layered sheet-like 2D Mo 2 CT x on the substrates was identified using the FESEM images. The sensor is found functional from room temperature to high-temperature conditions (30–250 °C). On the normal humid condition of 30% RH, the gas sensing response of the fabricated sensor is almost double in comparison with the crystalline silicon/Mo 2 CT x sensor at 250 °C. The introduction of humidity leads to further enhancement of the sensing response from 25% to 32%. Moreover, the fabricated sensor presents a good sensing response at room temperature (30 °C) for a CO 2 concentration of 50 ppm along with a fast response and recovery times of 32 and 45 s with a high degree of stability. The fabrication of CO 2 sensor using Mo 2 CT x on porous silicon substrate exhibited high sensing response, long-term stability along with fast response and recovery at room temperature. • Porous silicon/Mo 2 CT x gas sensors for the detection of CO 2 gas. • The fabricated sensor is capable of working from 30 to 250 °C. • Room temperature CO 2 sensing at 50 ppm. • Fast response and recovery of 30 and 45s at room temperature (30 °C). • Humidity enhances the percentage sensitivity.