Origin of Visible Light Photoactivity of Reduced Graphene Oxide/TiO₂ by in Situ Hydrothermal Growth of Undergrown TiO₂ with Graphene Oxide

Abstract

Graphene-related−TiO 2 (G−TiO 2 ) nanocomposites show enhanced photocatalytic performance, not only due to promoting photogenerated electrons migration but also by extending optical absorption to the visible light range. However, little is known about the origin of the visible light activity, which seems to depend much on the precursor of the titanium source. In this study, an efficient visible light active G− TiO 2 -413 was prepared by hydrothermally treating a graphene oxide (GO) suspension and TiO 2 sol with undergrown TiO 2 nanoparticles at 413 K. According to XRD, DRS, TEM, FTIR, Raman, and ESR analyses, when in situ growing TiO 2 nanoparticles from hydrolyzed titanium alkoxides in hydrothermal conditions, a strong chemical interaction appears at the interface of GO sheets and the underdeveloped loosely packed polymeric Ti−O−Ti skeletons, so as to facilitate retaining more alkoxyl groups, inducing crystal disorders, and creating oxygen vacancies. All of these contribute to the significantly enhanced visible light activity of G−TiO 2 -413. This sheds new light on the development of visible light responsive TiO 2 -based photocatalysts via surface modification approaches.

Graphene-wrapped hierarchical TiO2 nanoflower composites with enhanced photocatalytic performance

“…RGO shows peaks at 1718 cm -1 (C=O), 1577 cm -1 (skeletal vibration), 1399 cm -1 (C-OH), and 1246 cm -1 (C-O-C). 203 The TiO2 materials share a common broad peak at ~3400 cm -1 (-OH) associated with the adsorption of water. The…”

Photochemical stability and reactivity of graphene oxide

“…Williams et al [8] synthesized a hybrid rGO-TiO 2 material by irradiating a suspension containing TiO 2 nanoparticles and GO. The use of rGO was proposed by several groups for the preparation of highly photoactive composite materials based on titanium dioxide for the catalytic oxidation of aqueous organic pollutants [9][10][11][12][13][14], in order to exploit the high charge mobility of graphene and to maximize the photocatalytic efficiency by hindering the process of charge recombination.…”

Recent Advances in Graphene Based TiO2 Nanocomposites (GTiO2Ns) for Photocatalytic Degradation of Synthetic Dyes

“…The as-fabricated hybrid composites presented distinct advantages over the traditional methods in terms of the well-confined TiO 2 morphology and the formation of Ti-C bonds between TiO 2 nanoroads and rGO simultaneously. Long et al [180] used the hydrothermal method to prepare efficient visible light active GTiO 2 Ns by using a GO suspension and TiO 2 sol with undergrown TiO 2 nanoparticles at 413 K. The study of obtained materials demonstrated high chemical interaction at the interface of GO sheets and the polymeric Ti-O-Ti structure that facilitated the retaining of more alkoxyl groups; the induced crystal disorders and oxygen vacancies contributed positively to the performance of the obtained photocatalyst.…”