Improving the photocatalytic performance of graphene–TiO2 nanocomposites via a combined strategy of decreasing defects of graphene and increasing interfacial contact

Abstract

Incessant interest has been shown in the synthesis of graphene (GR)-semiconductor nanocomposites as photocatalysts aiming to utilize the excellent electron conductivity of GR to lengthen the lifetime of photoexcited charge carriers in the semiconductor and, hence, improve the photoactivity. However, research works focused on investigating how to make sufficient use of the unique electron conductivity of GR to design a more efficient GR-semiconductor photocatalyst have been quite lacking. Here, we show a proof-of-concept study on improving the photocatalytic performance of GR-TiO(2) nanocomposites via a combined strategy of decreasing defects of GR and improving the interfacial contact between GR and the semiconductor TiO(2). The GR-TiO(2) nanocomposite fabricated by this approach is able to make more sufficient use of the electron conductivity of GR, by which the lifetime and transfer of photoexcited charge carriers of GR-TiO(2) upon visible light irradiation will be improved more efficiently. This in turn leads to the enhancement of visible-light-driven photoactivity of GR-TiO(2) toward selective transformation of alcohols to corresponding aldehydes using molecular oxygen as a benign oxidant under ambient conditions. It is anticipated that our current work would inform ongoing efforts to exploit the rational design of smart, more efficient GR-semiconductor photocatalysts for conversion of solar to chemical energy by heterogeneous photocatalysis.

Graphene-wrapped hierarchical TiO2 nanoflower composites with enhanced photocatalytic performance

“…In order to further improve the performance of photocatalytic materials, composites consisting of TiO2 and carbonaceous materials have been explored. 7 Carbonaceous materials such as carbon nanotubes, 184,185 activated carbons, 186,187 and graphene 188,189 have been combined with TiO2 to create composites with improved performance. Graphene in particular has been shown to provide several advantages to pure TiO2 photocatalysis: 123 First, graphene consists of a highly conjugated planar surface which allows for preferential adsorption of aromatic compounds such as methylene blue (MB) through π-π stacking.…”

Ag3PO4-TiO2-Graphene Oxide Ternary Composites with Efficient Photodegradation, Hydrogen Evolution, and Antibacterial Properties

“…The G band is derived from the stretching of sp 2 -hybridized carboncarbon bonds, and is highly sensitive to strain effects in the sp 2 system within graphene sheets. Furthermore, the intensity ratio of D and G bands, ID/IG, can be considered as a measure of the relative concentration of local defects or interferences, i.e., to estimate the changes of sp 3 graphite oxide converting to sp 2 graphene [40]. Therefore, an increment of ID/IG value implies an increase in the number of defects.…”

Nanocarbons with Different Dimensions as Noble-Metal-Free Co-Catalysts for Photocatalysts

“…However, graphene is not easy to be dispersed in water, which makes it difficult to contact semiconductor nanoparticles with graphene in aqueous solution. GO with hydrophilic oxygen-containing groups is easy to be dispersed in aqueous solution, so GO is usually used as a graphene precursor [73][74][75]. Zhu et al [76] employed GO and TiCl3 as starting materials and synthesized graphene/TiO2 composites.…”