In order to clarify the reason for the improvement of photocatalytic activity, the energy band structure of ZnO–Au
composite was investigated. It is reported that the work function of Au and ZnO are 5.1 eV and 5.2 eV respectively
Fig. 5. One-dimensional ZnO nanostructures fabricated by spinning solutions with different viscosity (a, b) sample 6 and (c, d) sample 7. Fig. 6. Schematic illustration for the possible formation mechanism of ZnO nanotubes. 524 X. Dong et al. / Ceramics International 42 (2016) 518–526 [25,26], and thus the Fermi energy level of Au is higher than that of ZnO.