Elevating selective ethanol detection based on unlocking the potential of accordion structured MXene

Abstract

Two-dimensional (2D) transition-metal carbides (Ti3C2Tx) MXene have received much attention due to their exciting prospects for application in gas sensing. Large surface area, metallic conductivity, and the functionalization potential all are key characteristics of MXene. These materials have optimum gas selectivity and responsiveness among 2D materials. By using HF etching, we developed exfoliated MXene from MAX phase of Ti3AlC2. The William-Hall (W-H) plot estimated the size of the crystallite to be 7.95 nm. The calculated optical band gap was found 1.53 eV. The almost disappearance of aluminum (Al) layers was confirmed by the XRD(X-ray diffraction) peak shift, EDS and XPS analysis and the accordion-like morphology confirmed by FESEM images. The specific surface area of synthesized MXene was found to be 39.00 m2g-1, while the pore volume of MXene was estimated as 0.0755852 cm3g-1 and the pore diameter was evaluated as 3.42782 nm. The experimental findings demonstrate the fact that Ti3C2Tx incorporation improves the sensitivity, the repeatability, and the selectivity of chemo-resistive sensors that are sensitive to VOCs (volatile organic compounds) such as acetone, ethanol, methanol, propanol, and hexane. The fabricated MXene based sensor was tested under exposure of aforementioned VOCs at 600 ppm. The initial finding illustrates that among these, ethanol is the most sensitive VOC. The fabricated Ti3C2Tx sensor yielded response (%) at the concentrations of 50, 100, 200, 300, 400 and 500 ppm as 1.78, 2.63, 3.42, 4.28, 5.05, and 5.47%, respectively under purging ethanol. The maximum response at room temperature (RT) operable ethanol sensor was calculated as 5.65% at 600 ppm under 40% of relative humidity (RH). The outcomes demonstrate rapid responses/recovery of 5s and 8s, respectively.