Ultra-low loading of Ag3PO4 on hierarchical In2S3 microspheres to improve the photocatalytic performance: The cocatalytic effect of Ag and Ag3PO4

- Ag3PO4/In2S3 composites with ultra-low loading of Ag3PO4 were prepared.
- Loading of ultra-low Ag3PO4 greatly improved the activity of In2S3.
- Ag-Ag3PO4 served as cocatalyst during photocatalysis.
- A Z-scheme mechanism among Ag/Ag3PO4/In2S3 was proposed.
- The activity enhancement was also observed over Ag3PO4/ZnIn2S4 composites.

Ag3PO4/In2S3 composite photocatalysts with ultra-low loading of Ag3PO4 (0.017 ∼ 4.89 wt %) were prepared by a facile precipitate method and characterized by XRD, SEM, TEM, HRTEM, BET, DRS and XPS techniques. The as-obtained composites were employed to degrade different kinds of organic pollutants (dyes and colorless pollutants) in aqueous solution under visible light irradiation. The Ag3PO4/In2S3 composites exhibited excellent adsorption capacity and photocatalytic activity. The optimal composite with 0.086 wt % Ag3PO4 content exhibited the highest photocatalytic activity, which could degrade almost all dyes (MO, MB and RhB) within 7 min of light irradiation and more than 50% of phenol and salicylic acid after 3 h of irradiation. Recycling experiments confirmed that the Ag3PO4/In2S3 catalysts had superior cycle performance and structural stability. The photocatalytic activity enhancement of Ag3PO4/In2S3 composites could be mainly attributed to the efficient separation of photogenerated charge carriers through a Z-scheme system composed of Ag3PO4, Ag and In2S3, in which Ag nanoparticles acted as the charge transmission bridge. The high photocatalytic stability was ascribed to the successful inhibition of the photocorrsion of both In2S3 and Ag3PO4 by transferring the photogenerated holes and electrons from them to Ag, respectively. This study indicated the application of Ag-Ag3PO4 as cocatalyst and provided a new way to design and prepare high-efficiency and stable photocatalysts for photocatalytic decontamination of organic pollutants.

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