▎ 摘　　要

Semiconductor driven photocatalysis has galvanized great attention as it holds tremendous promise to address the worldwide environmental and energy issues. Photocatalysis, in which photons are used for redox reactions, is at the central point to achieve this goal. The heterogeneous photocatalysts with integrated functional nanocomposites can combine the advantages of different nano-composites to overcome the drawbacks of single nano-photocatalysts. Coupling of TiO2 with narrow band gap semiconductor nanocomposites has been a strategy used by researchers to obtain visible light active photocatalysts. In this work, graphene has been used to improve the performance of photocatalysts based on its great charge conductivity as well as other exciting properties. The edge effect has been removed by introducing the 2D graphene into circular rolls inserted in the 65-140 nm TiO2, TiO2-CuO (TC), and TiO2/ZnO/Bi2O3 (TZB) nanofibers (NFs) and free electrons can only travel in specific direction along the axis of the TiO2, TiO2-CuO (TC), and TiO2/ZnO/Bi2O3 (TZB) (NFs). The resulting (NFs) has less band-gap energy that facilitates harvesting of the visible light spectrum. The graphene incorporation helps to harvest more energy from the entire UV-vis spectrum and almost doubled the surface area of the (NFs) when maximum amount of graphene is embedded into the (NFs). The T-Gr, TC-Gr and TZB-Gr photocatalyst, after optimized with as much as 32.18%, 16.87% and 26.5% respectively by mass of graphene in the (NFs), has superior photoactivity in degradation of formaldehyde under solar irradiation. The kinetics and fundamental mechanism of formaldehyde degradation are also addressed. The graphene insertion controls the work function of photocatalysts, which is critical for photocatalytic reactions.