Abstract
Two-dimensional Ti3C2 MXenes can be used to fabricate hierarchical TiO2 nanostructures that are potential photocatalysts. In this study, the photodecomposition of organic dyes under solar light was investigated using flower-like TiO2@Ti3C2, deposited using narrow bandgap Ag3PO4. The surface morphology, crystalline structure, surface states, and optical bandgap properties were determined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption analysis, and UV-Vis diffuse reflectance spectroscopy (UV-DRS). Overall, Ag3PO4-deposited TiO2@Ti3C2, referred to as Ag3PO4/TiO2@Ti3C2, demonstrated the best photocatalytic performance among the as-prepared samples, including TiO2@Ti3C2, pristine Ag3PO4, and Ag3PO4/TiO2 P25. Organic dyes, such as rhodamine B (RhB), methylene blue (MB), crystal violet (CV), and methylene orange (MO), were efficiently degraded by Ag3PO4/TiO2@Ti3C2. The significant enhancement of photocatalysis by solar light irradiation was attributed to the efficient deposition of Ag3PO4 nanoparticles on flower-like TiO2@Ti3C2 with the efficient separation of photogenerated e-/h+ pairs, high surface area, and extended visible-light absorption. Additionally, the small size of Ag3PO4 deposition (ca. 4-10 nm diameter) reduces the distance between the core and the surface of the composite, which inhibits the recombination of photogenerated charge carriers. Free radical trapping tests were performed, and a photocatalytic mechanism was proposed to explain the synergistic photocatalysis of Ag3PO4/TiO2@Ti3C2 under solar light.