The enhanced photo-stability of defective Ag3PO4 tetrahedron prepared using tripolyphosphate

Ag3PO4 is an excellent photocatalyst under visible light irradiation. However, the low stability due to photo-corrosion is still an obstacle in its application. It is a big challenge to improve stability using synthesis modification. Here, the photocatalyst stability enhancement was successfully prepared by tripolyphosphate. Photocatalyst was prepared by reacting AgNO3 solution with STPP (sodium tripolyphosphate) solution to form a white suspension. The addition of phosphate solution to the white suspension produces yellow Ag3PO4 with a new type of defective photocatalyst. The XPS measurement showed that the increase of STPP concentration significantly decreased the Ag/P atomic ratio, indicating the silver vacancy formation on the surface of Ag3PO4. The photocatalytic reaction formed a metallic Ag with a lower d-space in the cube structure occurred in the silver vacancy of Ag3PO4. This defect increases the interaction of metallic silver and Ag3PO4. The enhanced photo-stability might be induced by metallic silver that can act as a photogenerated electron acceptor.