Ag3PO4-Deposited TiO2@Ti3C2 Petals for Highly Efficient Photodecomposition of Various Organic Dyes under Solar Light

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.