Thin silica shell on AgPO nanoparticles augments stability and photocatalytic reusability.

Semiconductor photocatalysts are promising cost-effective materials for degrading hazardous organic contaminants in water. AgPO is an efficient visible-light photocatalyst for the oxidation of water and dye degradation. The excited AgPO photocatalyst uses a hole to oxidise water or organic contaminants except the electron, which reduces Ag to Ag. In the present study, the inherited disadvantage was overcome by a thin silica shell overcoating on AgPO nanoparticles. The silica-coated AgPO nanoparticles retain the photocatalytic activity even after five cycles of photodegradation, while the bare AgPO 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 formation on the surface of bare AgPO is greater than that on silica-coated AgPO, which declines the photocatalytic activity of AgPO after five cycles of photodegradation. Electrochemical studies identified that the intermediates, such as OH˙ and O, 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.