Co(II)-grafted Ag3PO4 photocatalysts with unexpected photocatalytic ability: Enhanced photogenerated charge separation efficiency, photocatalytic mechanism and activity.

Since the photocatalytic capability is determined by the separation and transmission efficiency of photoinduced charges, its improvement remains a challenge for development of efficient photocatalysts. Here, we made large improvement on the surface of Ag3PO4 using Co(II)-grafted Ag3PO4 by a hydrothermal method. During the photocatalytic process, Co(II) was oxidized to Co(III) by the photogenerated holes under visible light radiation, which enhanced the separation efficiency of photogenerated charges. Meanwhile, the Co(III) as-formed could oxidize dye molecules, which recovered the Co(II). The synergy of Co(II) and Ag3PO4 greatly promoted the separation and transmission efficiency of the photogenerated charges, and severely improved the photocatalytic activity of Ag3PO4. The surface grafted Co(II) on Ag3PO4 is responsible for the enhancement of photocatalytic activity.