Effect Of Surface Modification On The Photoelectrochemical Properties Of ZnO And The Density Functional Theory Study

Because of the excellent performance of low cost, high stability, high photocatalytic activity, low toxicity etc., ZnO is recognized as excellent semiconductor photocatalyst. Compared to TiO2, ZnO has excellent electron mobility. Forthermore, it can significantly improve the photocatalytic and Photoelectrochemical properties of ZnO by controlling the morphology of ZnO and modifying ZnO. In this article, the photocatalytic and photoelectrochemical performance of Zn O materials were studied on the base of surface modified porous ZnO nanorods(ZnO NRs). And the mechanism of the enhancement of photocatalytic and photoelectrochemical performance of element doped ZnO were further studied by first-principle density functional theory calculation.In this paper, first the porous ZnO NRs were prepared by hydrothermal method, and then the ZnO NRs were modified by metal Ag and carbon dots(C-dots) for testing the photocatalytic and photoelectrochemical properties. The results of photocatalytic degradation performance showed that the Ag and C-dots modified porous ZnO NRs showed significantly enhancement of photocatalytic performance comparing with the porous ZnO NRs. And the mole ratio 3% Ag modified ZnO NRs and 1.2wt% C-dots modified ZnO NRs showed the best photocatalytic performance among the series modified ZnO NRs. Further photocatalytic degradation of phenol showed that the chemical state of Ag significantly influence the degradation process of phenol. The metal Ag and C-dots mainly acted as the supporter for the photogenerated electrons, which could enhance the efficient separation of photogenerated electrons and holes and further the photocatalytic performance.In order to study the influence of impurity element modification on the physical properties of ZnO semiconductor, the mechanism of its photocatalytic properties is revealed. The electronic structures and optical properties of metal(Fe, Cu, Cd) and nonmental(B, N, S) doped were investigated by first-principle density functional theory calculation. A deeper investigation indicate that different doping atoms in substitution of zinc and oxygen atoms can indeed alter the near-Fermi level DOS of ZnO and their electronic structures. Comparing with pure ZnO, the optical properties of ZnO are improved after doped with different atoms. By doping elements, the ZnO band structure, electronic density of States and optical properties can be changed, that is beneficial to improve the photocatalytic performance of ZnO.