MXene/Co₃O₄ Layered Composites for Acetone Gas Sensing

Accordion-like multilayered Ti 3 C 2 T x 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/Co 3 O 4 was synthesized via a self-assembly method by coating thin-layered MXene with Co 3 O 4 nanosheets (Co 3 O 4 NS) to enhance acetone sensing performance, especially at a high temperature of up to 200 °C. An interfacial electric field arises between Ti 3 C 2 T x MXene and Co 3 O 4 NS because of their different work functions. Due to a synergistic effect of the interfacial electric field and the surface-coated Co 3 O 4, MXene/Co 3 O 4 achieves the highest response intensity for acetone concentrations ranging from 0.1 to 1000 ppm, surpassing the individual sensitivities of Co 3 O 4 NS and MXene alone. Remarkably, the detection limit of MXene/Co 3 O 4 (0.1 ppm) outperforms those of Co 3 O 4 NS and MXene. Employing the AdaBoost algorithm for machine learning, MXene/Co 3 O 4 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/Co 3 O 4 heterojunction calculated by density functional theory is −0.97 eV, indicating easier adsorption than MXene and Co 3 O 4 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.