The Quaternary System Of Ag2s/Zns Co-Modified Zno/Tio2 Nanotree Arrays: Excellent Photocatalysis And Photoelectrochemistry Performance

The ZnO/TiO2 nanotree arrays were prepared by hydrothermal and sol-gel methods, and then the quaternary system of Ag2S/ZnS co-modified ZnO/TiO2 nanotree arrays was obtained by the vulcanization process and cation exchange method. Compared with TiO2 nanorod arrays, the formation of ZnO/TiO2 heterojunction nanotree arrays promotes the separation of electron-hole pairs, which improves the photoelectrochemical and photo catalytic properties. The core-shell structure formed by the ZnS passivation layer and ZnO not only prevents the decomposition of ZnO, but also enhances the light absorption caused by light scattering and promotes the rapid transfer of photogenerated charges. In addition, the modification of Ag2S can reduce the bandgap width of the composite, red-shift the optical absorption edge and improve the optical absorption intensity. The results show that bandgap width of the Ag2S/ZnS/ZnO/TiO2 quaternary system is reduced to 1.95 eV. The transient photo current density (0.15 mA/cm(2)) and photocatalytic rate constants (6.43 x 10(-3) min(-1)) of the Ag2S/ZnS/ZnO/ TiO2 quaternary system are 11 and 6.5 times higher than those of pure TiO2, respectively. It is shown that the coordinated action of ZnS and Ag2S not only improves the light absorption intensity, but also greatly promotes the transfer of photogenerated charge and prevents the complexation of electron-hole pairs, which improves the photoelectrochemical and photocatalytic properties.