OPTIMAL PARTICLE SIZE OF Ag3PO4 PHOTOCATALYSTS ACHIEVED BY pH-CONTROLLED SYNTHESIS

DOI: 10.18173/2354-1059.2025-0038

Tóm tắt

Silver orthophosphate (Ag3PO4, APO) was synthesized by a simple co-precipitation method using AgNO3 and K2HPO4.3H2O as precursors. The pH of the precursor solution was adjusted by adding a HNO3 solution (0.5 M), which effectively controlled the particle size without altering the crystal structure. The samples in this work were prepared as APO–xH, where x represents the volume (mL) of HNO₃ added (0, 0.5, 1.0, 1.5, 2.0, and 2.5 mL). The particle size decreased systematically from ~450 nm (APO–0H) to ~150 nm (APO–2.5H). APO–1.5H, with an average size of ~250 nm, represented the “optimal size,” achieving complete degradation of 10 ppm Rhodamine B within 14 minutes under visible light irradiation from a 50 W compact fluorescent lamp, twice as fast as pristine APO. In preliminary cycling performed only on the reference APO–0H sample, the RhB degradation efficiency decreased to ~30% by the fifth cycle under visible-light irradiation. These findings confirm that the optimal photocatalytic activity of Ag3PO4 does not originate solely from increased surface area but from a balance between particle size, morphology, and structural stability. This work provides a simple approach to tailor Ag3PO4 for efficient visible-light-driven water treatment.