Self-assembly of defect-rich graphene oxide nanosheets with Na₂Ti₃O₇nanowires and their superior absorptive capacity to toxic dyes

Abstract

Graphene sheets, a flexible 2D material with excellent absorptive capacity, have great potential as absorbing materials. However, this material has always suffered from irreversible aggregation and thus loses the abundant active sites and large surface area. In this paper, large-scale graphene oxide (GO) sheets were cut and reduced to tiny reduced graphene oxide (RGO) sheets by a cell-break sonicator, for producing numerous defects, which are the center of chemisorption. Furthermore, sodium titanate nanowires functioned as a framework to help to disperse the tiny RGO sheets uniformly. And, in turn, the flexible tiny RGO sheets glued robust nanowires into a free-standing membrane. This novel composite membrane exhibited an ultra-high decoloration efficiency of 99.8% of rhodamine B in a continuous flow mode, and an outstanding absorptive capability of 1.30 × 10 mol g correlated to RGO content in batch reaction, which is about two orders of magnitude higher than other reported graphene-based absorbents. In addition, an efficient and feasible method without any heat treatment for regenerating the membrane is illustrated, and the recycled membrane retains superior decoloration efficiency. The excellent absorptive performance indicates the framework-based disperse strategy has great potential for the construction and application of defect-rich graphene.

Visible-light promoted catalytic activity of dumbbell-like Au nanorods supported on graphene/TiO2 sheets towards hydrogenation reaction

“…The value of the I D /I G of Au/GO/TiO 2 is only 0.78. In sharp contrast, the I D /I G values of Au/RGO/TiO 2 -1 and Au/RGO/TiO 2 -4 increased to be 1.09 and 1.05, revealing that the RGO is endowed with new defects and disordered structures after reduction, which is consistent with our previous reports [21,22]. The TEM images of the RGO sheet in Au/RGO/TiO 2 -1 and Au/RGO/TiO 2 -4 (figure S2) further confirmed the presence of disorder structures in the form of pores, cracks and wrinkles.…”

“…Fabrication of ternary Au/graphene/TiO 2 sheets M-Au-3 nanorods were selected to fabricate the ternary Au/graphene/TiO 2 sheets in the following experiments. The GO sheets were prepared by the modified Hummer's method in our previous work [21,22]. To fabricate the TiO 2 nanowires, 50 mg of P25 powder was hydrothermally reacted with 16 ml of 10 mol L −1 NaOH at 200 °C for 20 h, followed by calcination at 750 °C for 3 h in air.…”

“…Peaks at ∼1340 cm −1 and 1590 cm −1 are associated with the D band and G band (labeled 7 and 8), respectively. In principle, the D band commonly represents disordered sp 3 carbon atoms, and the G band origins from the ordered sp 2 carbon atoms [22]. Therefore, the intensity ratio of the D band to G band (i.e.…”

“…This obstacle could be dissolved to a certain degree by reducing the pristine GO to RGO sheets. But the resultant hydrophobic nature in RGO unavoidably makes it easily aggregate together and lose the extra high surface areas due to π-π restacking to minimize surface energies [21,22]. The tremendous shrinkage of the surface areas of RGO sheets inhibits their wide applications in catalysis.…”

Electronic textiles based on aligned electrospun belt-like cellulose acetate nanofibers and graphene sheets: portable, scalable and eco-friendly strain sensor

“…GO sheets were fabricated from graphite flakes according to a modified Hummers method [25]. GO with a concentration of 20 mg ml −1 was then uniformly dispersed on CA mats by spin coating.…”