Interfacial carbon-regulated charge transfer and ROS evolution in Ag₃PO₄ for enhanced photo-persulfate activation.

Area of Science:

• Environmental Science and Engineering
• Materials Science
• Catalysis

Background:

• Conventional silver phosphate (Ag3PO4) photocatalysts exhibit limitations due to photocorrosion and inefficient reactive oxygen species (ROS) evolution.
• Tetracycline (TC) is a persistent organic pollutant requiring effective degradation strategies.

Purpose of the Study:

• To construct a biochar-supported Ag3PO4 (BC/Ag3PO4) composite to improve interfacial charge transfer and ROS evolution.
• To investigate the synergistic effect of the BC/Ag3PO4 composite in a photo-peroxydisulfate (photo-PS) system for tetracycline degradation.
• To elucidate the underlying mechanisms of enhanced degradation and catalyst stability.

Main Methods:

• Synthesis of biochar-supported Ag3PO4 (BC/Ag3PO4) composite.
• Evaluation of the BC/Ag3PO4 composite in a coupled photo-peroxydisulfate (photo-PS) system for tetracycline degradation.
• Mechanistic studies involving interfacial electron transfer, ROS generation, and catalyst stability assessment.

Main Results:

• The BC/Ag3PO4 composite demonstrated a significant synergistic enhancement in TC degradation, with a rate constant 6.61- and 12.92-fold higher than individual photocatalysis and PS systems, respectively.
• Biochar (BC) acted as an interfacial electron mediator and adsorption regulator, facilitating electron redistribution and promoting PS activation, leading to a hybrid ROS microenvironment dominated by OH• and SO4•−.
• The composite system suppressed Ag3PO4 photocorrosion and maintained over 92.66% catalytic activity after five cycles, while accelerating TC degradation and directing it to less toxic pathways.

Conclusions:

• The BC/Ag3PO4 composite effectively reconfigures interfacial charge transfer and ROS evolution in the photo-PS system, leading to superior TC degradation efficiency and catalyst stability.
• The interface-driven strategy provides mechanistic insights for designing advanced carbon-based semiconductor composites for environmental remediation.
• This approach couples high degradation efficiency with detoxification, offering a promising solution for treating organic pollutants.