Carbon Dot-Doped Titanium Dioxide Sheets for the Efficient Photocatalytic Performance of Refractory Pollutants

Broad solar light harvesting and fast photoinduced electron-hole migration are two critical factors for the catalytic capacity of photocatalytic system. In this study, novel visible light-driven carbon dot-TiO₂ nanosheet (CD-TN) photocatalysts are successfully prepared by loading CDs on the surface of TNs through the hydrothermal method. The microstructure, chemical components, and optical properties of the prepared samples are characterized via X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, UV-visible diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy analysis. Congo red (CR), rhodamine B (RhB), and tetracycline (TC) are selected as pollutants to assess the catalytic performance of CD-TNs. As expected, the removal efficiencies of CD-TNs for CR, RhB, and TC are 94.6% (120 min), 97.2% (150 min), and 96.1% (60 min), respectively, obviously higher than that of pure TNs. The enhanced degradation efficiency of CD-TNs is predominantly ascribed to the merits of CDs (excellent up-conversion property and electron transfer property). Moreover, according to the several degradation cycles, CD-TNs possess the excellent stability, having removed 93.3% of CR after 120 min irradiation.