MXene/Co₃O₄ Layered Composites for Acetone Gas Sensing

Accordion-like multilayered Ti3C2Tx MXene has garnered significant attention due to its high conductivity and sensitivity, thereby being promising for acetone sensing. However, the limited stability of thin-layered MXene hinders its applications at high temperature. In this study, MXene/Co3O4 was synthesized via a self-assembly method by coating thin-layered MXene with Co3O4 nanosheets (Co3O4 NS) to enhance acetone sensing performance, especially at a high temperature of up to 200 °C. An interfacial electric field arises between Ti3C2Tx MXene and Co3O4 NS because of their different work functions. Due to a synergistic effect of the interfacial electric field and the surface-coated Co3O4, MXene/Co3O4 achieves the highest response intensity for acetone concentrations ranging from 0.1 to 1000 ppm, surpassing the individual sensitivities of Co3O4 NS and MXene alone. Remarkably, the detection limit of MXene/Co3O4 (0.1 ppm) outperforms those of Co3O4 NS and MXene. Employing the AdaBoost algorithm for machine learning, MXene/Co3O4 demonstrated 99.76% accuracy in distinguishing acetone from six other gases, holding great potential for practical gas sensing applications. The acetone adsorption energy of the MXene/Co3O4 heterojunction calculated by density functional theory is −0.97 eV, indicating easier adsorption than MXene and Co3O4 NS. This study presents a facile approach to fabricate MXene/metal oxide-based materials for acetone sensing, offering promising prospects in gas sensor development and showing universal significance for gas sensing fabrications.