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

Abstract

Synthetic dyes are widely used in textile, paper, food, cosmetic, and pharmaceutical industries. During industrial processes, some of these dyes are released into the wastewater and their successive release into rivers and lakes produces serious environmental problems. TiO 2 is one of the most widely studied and used photocatalysts for environmental remediation. However, it is mainly active under UV-light irradiation due to its band gap of 3.2 eV, while it shows low efficiency under the visible light spectrum. Regarding the exploration of TiO 2 activation in the visible light region of the total solar spectrum, the incorporation of carbon nanomaterials, such as graphene, in order to form carbon-TiO 2 composites is a promising area. Graphene, in fact, has a large surface area which makes it a good adsorbent for organic pollutants removal through the combination of electrostatic attraction and π-π interaction. Furthermore, it has a high electron mobility and therefore it reduces the electron-hole pair recombination, improving the photocatalytic activity of the semiconductor. In recent years, there was an increasing interest in the preparation of graphene-based TiO 2 photocatalysts. The present short review describes the recent advances in TiO 2 photocatalyst coupling with graphene materials with the aim of extending the light absorption of TiO 2 from UV wavelengths into the visible region, focusing on recent progress in the design and applications in the photocatalytic degradation of synthetic dyes.

Graphitic Carbon Nitride and Titanium Dioxide Modified with 1 D and 2 D Carbon Structures for Photocatalysis

“…[35][36][37][38][39] Another possible application of these materials is the photocatalytic reduction of CO 2 to methane. [35][36][37][38][39] Another possible application of these materials is the photocatalytic reduction of CO 2 to methane.…”

Nano‐Graphene as Groundbreaking Miracle Material: Catalytic and Commercial Perspectives

“…are associated with the fabrication of monolayer two‐dimensional nano‐graphene by appropriate synthetic methods . Number of synthetic methods frequently are used in nano‐graphene synthesis, which may be broadly categories in‐(i) top‐down methods, and (ii) bottom‐up methods ,,. The top‐down method of nano‐graphene synthesis basically includes the exfoliation of graphite via mechanical, thermal, chemical synthesis, electrochemical expansion, electrostatic deposition, etc.…”

A Simple Route in Fabricating Carbon-Modified Titania Films with Glucose and Their Visible-Light-Responsive Photocatalytic Activity

“…As soon as the UV light was turned on, the photodegradation effect was detected immediately, but [NO] and [NO x ] then increased with time gradually. Because a higher calcining temperature would burn out partial carbonaceous species and accelerate grain growth, fewer adsorption sites could be provided for NO 3 − . Generally, NO 2 selectivity in a UV environment is lower than in visible light due to its stronger energy, promoting more NO 2 oxidized to NO 3 − .…”

“…Among all photocatalysts, titania has many competitive advantages, including high stability, low toxicity, favorable efficiency, and low price. Thus, titania is one of the most popular photocatalyst materials for water-purifying, deodorization, antifogging, sterilization, and solar energy generation [1][2][3]. For convenient manufacturing, powder-type titania is commonly provided in industry.…”