Fabrication And Photocatalytic Performance Of Graphene-TiO₂Composite Photocatalyst

As an advanced oxidation technology, photocatalysis has received wide attention in environmental pollution control. TiO2, with many advantages such as high activity, good chemical stability, corrosion resistance to light, low cost and non-toxicity, is regarded as the most promising green photocatalyst. However, its low photoconversion efficiency limits its practical application. Herein, we designed and fabricated graphene-TiO2composite photocatalyst, and promoted the practical application of photocatalysis via enhancing the energy efficiency profiting from the composite structure of graphene and TiO2. The main research content is as follows:Using graphite oxide and tetra-n-butyl titanate as precursors, the graphene-TiO2composite photocatalyst was fabricated by a two steps method. Firstly, the primary product was prepared by a hydrothermal process at433K for14h, and secondly, an anneal process for2h in873K was performed under Ar flow to convert amorphous TiO2to anatase. Observing with TEM, we found TiO2was nanoparticle form and attached on the surface of graphene. The result of XRD indicated that crystal phase of TiO2was anatase. According to the Raman patterns and XPS patterns, we can confirm the sample was composed of TiO2and graphene. In the photocatalysis experiment, the degradation ratio of methylene blue (MB) on graphene-TiO2composite photocatalyst was above1.2times that of TiO2. Furthermore, composite photocatalyst exhibited good stability. The holes governed the photocatalytic process and high pH value is favorable for the photocatalytic performance.In order to further improve the photocatalysis ability of the graphene-TiO2photocatalyst, the graphene-TiCh photonic crystal was synthetized by loading the graphene films obtained via an electrochemical reduction method on the surfaces of the TiO2photocatalysis materials with the inverse opals structure obtained by a sol-gel method. The TiO2in this photonic crystal composite was anatase, and the diameter of air spheres was around185nm. The photocatalysis capability of graphene-TiO2photonic crystal was investigated taking MB as target under UV light irradiation. The results showed that due to the band gap scattering effect and slow photon effect from photonic crystal, the kinetic constant using the graphene-TiO2inverse opals was1.8times as great as that of pristine graphene-TiO2nanocrystalline film.