A promising inorganic-organic Z-scheme photocatalyst Ag3PO4/PDI supermolecule with enhanced photoactivity and photostability for environmental remediation

Silver orthophosphate (Ag3PO4) based semiconductor photocatalysis have been widely investigated for environmental purification due to its strong oxidation ability. Yet, its poor photostability and low photoactivity hamper its extensive applications. Here, an inorganic-organic Z-scheme photocatalytic system for antibiotic degradation demonstrated high photoactivity and stability through the use of Ag3PO4/Perylene diimide organic supermolecule (PDIsm). The apparent rate constant of tetracycline hydrochloride (TC-H) degradation with Ag3PO4/PDIsm was 1.5 times that of Ag3PO4 and 8 times that of PDIsm. The photocatalytic activity of Ag3PO4/PDIsm toward TC-H still kept 65 % after four reuses, while pure Ag3PO4 only kept 22 %. We revealed that this high photoactivity and photostability arisen from the efficient carriers separation and the formation of direct Z-scheme junction. Importantly, this Z-scheme electron transfer pathway was confirmed by thorough experimental study and density functional theory (DFT) calculation. This work demonstrated the significant potential of Ag3PO4-based inorganic-organic Z-scheme photocatalyst in environmental remediation.