fig4

Figure 4. XPS spectrum of Au/ZnO before and after photocatalytic ozonation reactions. (A) Survey spectrum (0.1 wt% Au/ZnO); (B) XPS spectrum of O 1s (0.1 wt% Au/ZnO); (C) XPS peaks for Au 4f_7/2, Au 4f_5/2, Zn 3p_1/2 and Zn 3p_3/2 (0.1 wt% Au/ZnO); (D) XPS peaks for Au 4f_7/2, Au 4f_5/2, Zn 3p_1/2 and Zn 3p_3/2 (0.5 wt% Au/ZnO). XPS: X-ray photoelectron spectroscopy.