Direct synthesis of hydrogen fluoride-free multilayered Ti(3)C(2)/TiO(2) composite and its applications in photocatalysis

Ti(3)C(2)/TiO(2) hybrids are environment-friendly and exhibit excellent photocatalytic and hydrogen-generating power characteristics. Herein, a novel single-step method is proposed for fabricating multilayer structures in which TiO(2), generated from (NH(4))(2)TiF(6), wraps the Ti(3)C(2) MXene by etching Ti(3)AlC(2) with (NH(4))(2)TiF(6). The optimal reaction conditions for the etching of Ti(3)AlC(2) with (NH(4))(2)TiF(6) were systematically studied. The phase composition, morphology, and photophysical properties of the Ti(3)C(2)/TiO(2) hybrids were investigated using X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and UV–vis spectrophotometry. The thermal stability of the hybrids was investigated using thermogravimetric and differential thermal analyses. Along with the formation of Ti(3)C(2) MXene, Ti(3)AlC(2) reacted with (NH(4))(2)TiF(6) at 60 °C for 24 h to form hybrids surrounded by NH(4)TiOF(3) crystals. Subsequent reactions of these hybrids with H(3)BO(3) resulted in the conversion of NH(4)TiOF(3) crystals into TiO(2) and eventually into Ti(3)C(2)/TiO(2) hybrids. Furthermore, the photocatalytic activity of the Ti(3)C(2)/TiO(2) hybrids was measured by monitoring the photodegradation of methylene blue under ultraviolet light, which showed that the photocatalytic activity of the Ti(3)C(2)/TiO(2) hybrids was higher than that of the commercial anatase TiO(2) nanoparticles.