The heterojunction formed at the interface

(termed Schottky barrier) separates the photoinduced electron–hole pairs, thus suppressing charge recombination [16]. The enhancement of photocatalytic activity of graphene-based semiconductor–metal composites was first demonstrated by Kamat and co-workers in 2010 [18]. Following that, Zhang et al. [19], Shen et al. [20], and Zhou et al. [21] carried out one-step hydrothermal methods to prepare graphene-TiO2 hybrid materials and showed that the composites exhibited enhanced photoactivity towards organic degradation over bare TiO2. Fan et al. [22] fabricated P25-graphene composites by three different preparation methods, i.e., UV-assisted photocatalytic reduction, hydrazine reduction, and hydrothermal method, all of which possessed significantly Torin 2 supplier improved photocatalytic performance for H2 evolution from methanol aqueous solution as compared to pure P25. To the best of our knowledge, the study on the use of graphene-TiO2 composites on the photoreduction of CO2 is still in its infancy. This leads to our great interest in studying the role of graphene in the composite towards the photoreduction of CO2 into CH4 gas under visible light irradiation. In this paper, we present a simple solvothermal

method to prepare reduced graphene oxide-TiO2 this website (rGO-TiO2) composites using graphene oxide (GO) and tetrabutyl titanate as starting materials. During the reaction, the deoxygenation of GO and the Eltanexor deposition of TiO2 nanoparticles on rGO occurred simultaneously. The photoactivity of the as-prepared rGO-TiO2

composite was studied by evaluating its performance in the photoreduction of CO2 under visible light illumination. In contrast to the most commonly employed high-power halogen and xenon lamps, we used 15-W energy-saving light bulbs to irradiate the photocatalyst under ambient condition. This renders the entire process practically feasible and economically viable. The rGO-TiO2 composite was shown to exhibit excellent photocatalytic activity as compared to graphite oxide and pure anatase. Methods Materials Graphite powder, tetrabutyl titanate (TBT), acetic acid (HAc), and ethylene glycol (EG) were supplied by Sigma-Aldrich (St. Louis, MO, USA). All reagents were of analytical Ergoloid reagent grade and were used without further purification. Synthesis of reduced graphene oxide-TiO2 composite Graphite oxide was prepared from graphite powder by modified Hummers’ method [23–25]. The detailed experimental procedure is given in Additional file 1. To obtain GO sheets, graphite oxide was dispersed into distilled water (0.5 g L−1) and ultrasonicated for 1 h at ambient condition. The solution was then chilled to ≈ 5°C in an ice bath. Meanwhile, a titanium precursor composed of 1.5 mL TBT, 7.21 mL EG, and 1.14 mL HAc was also chilled to ≈ 5°C in an ice bath. The mixture was then added dropwise into the chilled GO aqueous solution under vigorous stirring.