**3.2. Ag3PO4–graphene composite**

The photocorrosion phenomenon of Ag3PO4 reduces the photocatalytic activity during the process. Up to now, some solutions have been put forward to improve its stability and photocatalytic properties under visible-light irradiation. Apart from its unique electronic properties [58], graphene has several other excellent attributes, such as the large theoretical specific surface area [57] and good chemical stability [59]. The large specific surface area of graphene facilitates the attachment of inorganic nanomaterials [144, 145]. Thus, the combina‐ tion of graphene and Ag3PO4 could be a good choice to construct a stable and efficient photocatalyst composite.

In one of our works, Ag3PO4/reduced graphite oxide (RGO) nanocomposites were synthesized to enhance the visible-light photocatalytic activity and the stability of Ag3PO4. The results show that the graphene content obviously affects the photocatalytic activity of Ag3PO4/RGO nanocomposites [134]. As shown in Fig. 7, among a series of Ag3PO4/RGO, the Ag3PO4/2.1 wt % RGO shows the best photocatalytic activity despite the degradation of MB or Methyl Orange (MO) solution. In addition, the Ag3PO4/RGO is more stable than pure Ag3PO4 since the RGO

**Figure 6.** SEM images of (a) branched, (b) tetrapod, (c) nanorod-shaped, and (d) triangular-prism-shaped Ag3PO4 crys‐ tals; (e) schematic illustration of the possible formation mechanism of Ag3PO4 crystals with four typical morphologies prepared under static and ultrasonic conditions; (f) variation of MB solution concentration against illumination time in the presence of branched, tetrapod, nanorod-shaped, triangular-prism-shaped, and irregular spherical Ag3PO4 prod‐ ucts. Reproduced with permission from ref. 143 © 2013 RSC.

can be used as protective coatings that inhibit the photocorrosion of Ag3PO4. Thus, the Ag3PO4/RGO nanocomposites with excellent photocatalytic performance and enhanced stability can find promising applications in addressing environmental protection issues.
