Room temperature gas sensing under UV light irradiation for Ti3C2Tx MXene derived lamellar TiO2-C/g-C3N4 composites

Two-dimensional layered-structured Ti3C2Tx MXene was prepared with hydrochloric acid and LiF. TiO2-C/g-C3N4 (TC-CN) composites were prepared by in situ growth method using melamine and Ti3C2Tx as a precursor. The structural properties of the as-prepared samples were characterized using SEM, XRD, and FT-IR measurements. The SEM image of TC-CN shows that it possesses an MXene-like lamellar structure. The gas sensing performances of TC-CN toward different volatile organic compounds gases at room temperature under UV light irradiation were investigated. The gas sensing results revealed that TC-CN showed excellent response value for 91 to 10 ppm ethanol at room temperature under UV light irradiation. The excellent gas sensing performances can be attributed to the UV light irradiation, construction of energy level dislocation, and lamellar structure of the composites, which leads to the enhancement of photoelectrons, reduction of the recombination of photoelectrons and holes, and high transportation of electrons in the TC-CN heterojunction, consequently enhancing the combination of the electrons and oxygen. Further, the possible gas sensing mechanism of the material was proposed and discussed.