Green Synthesis of Biphasic TiO₂–Reduced Graphene Oxide Nanocomposites with Highly Enhanced Photocatalytic Activity

Abstract

A series of TiO(2)-reduced graphene oxide (RGO) nanocomposites were prepared by simple one-step hydrothermal reactions using the titania precursor, TiCl(4) and graphene oxide (GO) without reducing agents. Hydrolysis of TiCl(4) and mild reduction of GO were simultaneously carried out under hydrothermal conditions. While conventional approaches mostly utilize multistep chemical methods wherein strong reducing agents, such as hydrazine, hydroquinone, and sodium borohydride are employed, our method provides the notable advantages of a single step reaction without employing toxic solvents or reducing agents, thereby providing a novel green synthetic route to produce the nanocomposites of RGO and TiO(2). The as-synthesized nanocomposites were characterized by several crystallographic, microscopic, and spectroscopic characterization methods, which enabled confrimation of the robustness of the suggested reaction scheme. Notably, X-ray diffraction and transmission electron micrograph proved that TiO(2) contained both anatase and rutile phases. In addition, the photocatalytic activities of the synthesized composites were measured for the degradation of rhodamine B dye. The catalyst also can degrade a colorless dye such as benzoic acid under visible light. The synthesized nanocomposites of biphasic TiO(2) with RGO showed enhanced catalytic activity compared to conventional TiO(2) photocatalyst, P25. The photocatalytic activity is strongly affected by the concentration of RGO in the nanocomposites, with the best photocatalytic activity observed for the composite of 2.0 wt % RGO. Since the synthesized biphasic TiO(2)-RGO nanocomposites have been shown to effectively reduce the electron-hole recombination rate, it is anticipated that they will be utilized as anode materials in lithium ion batteries.

Understanding the Electronic Structures of Graphene Quantum Dot Physisorption and Chemisorption onto the TiO2 (110) Surface: A First‐Principles Calculation

“…[18,19] The second approach has the shortcoming of multistep reaction pathways and leads to decrease in the photocatalytic activity due to the partial loss of active surface sites of the photocatalysts. [29,30] The subsequent theoretical work agrees with experiments that the graphene-TiO 2 periodic system has potentially high photocatalytic and photovoltaic performance. [21][22][23][24] This leads graphene/TiO 2 composites to be promising materials in applications of photocatalysts and solar cells.…”

“…The first strategy can decrease the electron-hole pair recombination rate, [16,17] but the synthesized materials typically suffer from a low concentration of dopants or possess low stability against photocorrosion. [25][26][27][28][29][30] Many experiments demonstrate that graphene-TiO 2 nanocomposites possess high stability, high photocatalytic activity, and enhanced photovoltaic properties. [20] Recently, composites of TiO 2 with nanoscale carbon materials have attracted much attention, especially in graphene because of its unique electronic structure and high stability.…”

Immobilization of TiO2 Nanoparticles on Chlorella pyrenoidosa Cells for Enhanced Visible-Light-Driven Photocatalysis

“…Figure 3c shows a Ti 2p XPS spectrum. Two peaks are observed at 464.4 eV and 458.6 eV, which are assigned respectively to the Ti 2p 1/2 and Ti 2p 3/2 spin-orbital splitting photoelectrons in the Ti 4+ state in anatase titanium [26]. As shown in Figure S3, the binding energy of Ti in the chlorella/TiO 2 composite does not exhibit evident changes, compared with that of the pure TiO 2 .…”

Photocatalytic degradation and antibacterial investigation of nano synthesized Ag3VO4particles @PAN nanofibers

“…have been successfully prepared and reported in relation to the decomposition of organic compounds or antibacterial activities utilizing visible light [13][14][15]. Photocatalysts based on semiconductor materials involve the generation of electron and hole pairs, migrating to the surface of the semiconductor, which contributes to the conversion of organic pollutants and inorganic pollutants into harmless substances and destruction of bacteria by a series of redox processes [16,17]. In the past decades, TiO 2 has been focused upon because of its outstanding photocatalytic activity, ready availability, longterm stability, and nontoxicity [18].…”