Highly responsive and stable room temperature acetic acid gas sensor based on nano-composite of MXene Ti3C2TX-NiCo2O4-MnO2

Designing novel acetic acid gas sensors is highly imperative for human health. Two-dimensional (2D) layered MXene Ti₃C₂T_x is becoming an emerging and promising material in gas sensing. In this manuscript, the hydrothermal method was used to synthesize MXenes Ti₃C₂T_x/Nb₂CT_x supported NiCo₂O₄-MnO₂ composites and pure materials. The structure, chemical composition and morphology of the samples were studied by SEM, EDS, TEM, HRTEM, XRD, BET, FTIR, UV-visible, XPS and Raman, justifying the successful synthesis of products. The layered structure of Ti₃C₂T_x enhanced the BET surface area and provided sufficient sites, which assisted the gas sensing improvement. The gas sensors were fabricated from synthesized products and were tested for different kinds of VOCs deeply. The results exposed that the gas sensor of Ti₃C₂T_x-NiCo₂O₄-MnO₂ (5% of Ti₃C₂T_x=NCO-Mn-Ti-5) was highly sensitive to 20 ppm acetic acid and very less responsive to all other VOCs (acetone, TMA, ethanol, methanol, formaldehyde, acetaldehyde, acetylene and xylene) at room temperature. The response (R_g/R_a) to 20 ppm acetic acid was 12.5 and the lowest detection limit was 0.05 ppm. Additionally, the sensor of NCO-Mn-Ti-5 revealed great stability/reproducibility, short response/recovery times and linearity between acetic acid concentration and response. The idea of the novel sensor (NCO-Mn-Ti-5) could be potentially useful in the field of sensors.