Thin silica shell on Ag3PO4 nanoparticles augments stability and photocatalytic reusability

Semiconductor photocatalysts are promising cost-effective materials for degrading hazardous organic contaminants in water. Ag3PO4 is an efficient visible-light photocatalyst for the oxidation of water and dye degradation. The excited Ag3PO4 photocatalyst uses a hole to oxidise water or organic contaminants except the electron, which reduces Ag+ to Ag-0. In the present study, the inherited disadvantage was overcome by a thin silica shell overcoating on Ag3PO4 nanoparticles. The silica-coated Ag3PO4 nanoparticles retain the photocatalytic activity even after five cycles of photodegradation, while the bare Ag3PO4 nanoparticles show a photocatalytic activity declined to half. The study demonstrates that the thin silica shell enhances the photostability, keeping the photocatalytic activity unaffected, even after several cycles of photodegradation of dyes. XPS analysis showed that the Ag-0 formation on the surface of bare Ag3PO4 is greater than that on silica-coated Ag3PO4, which declines the photocatalytic activity of Ag3PO4 after five cycles of photodegradation. Electrochemical studies identified that the intermediates, such as OH and O-2(-), formed during water oxidation play a crucial role in the photodegradation of dyes. This study can provide insights into the design of core-shell semiconductor nanostructures for reusable photocatalytic applications.

Automated summary

This study demonstrates the effectiveness of a thin silica shell overcoating on Ag3PO4 nanoparticles in improving their photocatalytic activity and stability for repeated cycles of dye degradation. The silica-coated Ag3PO4 nanoparticles exhibited retained photocatalytic activity even after five cycles, while the bare Ag3PO4 nanoparticles showed a significant decline in activity. The findings suggest that the design of core-shell semiconductor nanostructures can provide insights into the development of reusable photocatalytic materials.