fig4

Figure 4. (A and B) SEM images of 3DOM CaTiO₃-Au after photocatalytic reaction; (C) XPS Au 4f spectra of 3DOM CaTiO₃-Au before and after photocatalytic reaction; (D) electrostatic potential difference brought by oxidization of gold atoms (the left and the middle are cross-section view of yz and xz plane, respectively. The right is a 3-D view of the electrostatic potential difference. The positive values indicate an elevated electrostatic potential by the addition of oxygen atoms); (E) H₂ production from different substrates; and (F) the proposed mechanism.