Study on the Visible-Light Photocatalytic Performance and Degradation Mechanism of Diclofenac Sodium under the System of Hetero-Structural CuBi(2)O(4)/Ag(3)PO(4) with H(2)O(2)

Two kinds of CuBi(2)O(4)/Ag(3)PO(4) with different heterojunction structures were prepared based on the combination of hydrothermal and in-situ precipitation methods with surfactant additives (sodium citrate and sodium stearate), and their characteristics were systematically resolved by X-ray Diffraction (XRD), Brunauer–Emmett–Teller (BET), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope (SEM)/ High-resolution Transmission Electron Microscopy (HRTEM), UV-vis Diffuse Reflectance Spectra (DRS) and Photoluminescence (PL). Meanwhile, the photocatalytic properties of the catalysts were determined for diclofenac sodium (DS) degradation and the photocatalytic mechanism was also explored. The results indicate that both of the two kinds of CuBi(2)O(4)/Ag(3)PO(4) exhibit higher photocatalytic efficiency, mineralization rate, and stability than that of pure CuBi(2)O(4) or Ag(3)PO(4). Moreover, the catalytic activity of CuBi(2)O(4)/Ag(3)PO(4) can be further enhanced by adding H(2)O(2). The free radical capture experiments show that in the pure CuBi(2)O(4)/Ag(3)PO(4) photocatalytic system, the OH(•) and O(2)(•−) are the main species participating in DS degradation; however, in the CuBi(2)O(4)/Ag(3)PO(4) photocatalytic system with H(2)O(2), all OH(•), h(+), and O(2)(•−) take part in the DS degradation, and the contribution order is OH(•) > h(+) > O(2)(•−). Accordingly, the photocatalytic mechanism of CuBi(2)O(4)/Ag(3)PO(4) could be explained by the Z-Scheme theory, while the catalysis of CuBi(2)O(4)/Ag(3)PO(4) with H(2)O(2) follows the heterojunction energy band theory.