Direct synthesis of hydrogen fluoride-free multilayered Ti3C2/TiO2 composite and its applications in photocatalysis
Tao Wang, Li Zhu, Wanying Zhu, Hideki Kanda
Abstract
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.