Tunable Nanostructure of TiO₂/Reduced Graphene Oxide Composite for High Photocatalysis

Abstract

In this study TiO 2 /reduced graphene oxide (TiO 2 /rGO) bipyramid with tunable nanostructure was fabricated by two-step solvothermal process and subsequent heat-treatment in air. The as-synthesized anatase TiO 2 nanocrystals possessed morphological bipyramid with exposed dominantly by ( 101) facets. Polyethylenimine was utilized during the combination of TiO 2 and graphene oxide (GO) to tune the surface charge, hindering the restack of graphene during solvothermal process and resulting in 1 to 5 layers of rGO wrapped on TiO 2 surface. After a further calcination, a portion of carbon quantum dots (CQDs) with a diameter about 2 nm were produced owing to the oxidizing and cutting of rGO on TiO 2 . The as-prepared TiO 2 /rGO hybrid showed a highly photocatalytic activity, which is about 3.2 and 7.7 times enhancement for photodegradation of methyl orange with compared to pure TiO 2 and P25, respectively. We assume that the improvement of photocatalysis is attributed to the chemical bonding between rGO/CQDs and TiO 2 that accelerates photogenerated electron-hole pair separation, as well as enhances light harvest.

A Novel Approach for P25‐Carbon Dot Composite and the Reactive Oxygen Species Involved in the Visible Light Photocatalytic Mineralization of Rhodamine B

“…The main difference between P25/CD and P25/C‐dot composites is the extra peak at 1383 cm ‐1 in P25/C‐dot which is assigned to the epoxy C‐O stretching, an indication of the interactions between TiO 2 and the C‐dot. Typically Ti‐O‐C bond stretching is observed around 800 cm ‐1 in FTIR spectra for TiO 2 and C‐dot interaction in P25/C‐dot composite however it is difficult to distinguish the peak because of the broad of Ti‐O‐Ti peak in the 400‐900 cm ‐1 region ,. The Raman spectrum of P25 (Figure C) shows four strong peaks at 141, 398, 519, and 639 cm −1 corresponding to the E g(1) , B 1g(1) , A 1g + B 1g(2) , and E g(3) modes of anatase TiO 2 , respectively.…”

Investigations of Temperature Effect on the Conduction Mechanism of Electrical Conductivity of Copolymer/Carbon Black Composite

“…It is known that the addition of conducting charges to polymers allows the modification of polymers' physical properties, as well as the implementation of new features in the polymer host matrix (Blom et al, 1998;Bouknaitir et al, 2017;He et al, 2016). The investigation of dielectric properties as a function of frequency and temperature is one of the most convenient methods of studying the transport mechanisms of polymer nanocomposite (El Hasnaoui et al, 2014).…”

Selective growth of Ti3+/TiO2/CNT and Ti3+/TiO2/C nanocomposite photocatalysts for enhanced visible-light utilization to degrade organic pollutants by lowering the bandgap of TiO2

“…and photocatalytic degradation 4,9,10 . Among the methods for the elimination of dyes, photocatalytic degradation and adsorption are acknowledged as e cient, inexpensive, and environmentally friendly techniques.…”

“…Photocatalytic degradation of organic pollutants is advantageous because of its eco-friendly, safety, and low cost [9][10][11][12] . Semiconductor photocatalysts have attracted intensive attention because of their potential applications in dye-sensitized solar cells, pollutant degradation, biocatalysis, and photocatalytic hydrogen evolution.…”

“…In particular, titanium dioxide (TiO 2 ) nanomaterials have been commonly studied because of their low toxicity, superior photocatalytic activity, and good chemical and biological stability. However, two signi cant shortcomings of TiO 2 restrict its application to the UV region: its relatively wide bandgap (3.0-3.2 eV), and the rapid recombination of photoexcited electrons (e − ) and holes (h + ) in its lattice [9][10][11][12][13][14] .…”