Photocatalytic activity of Ag3PO4 and some of its composites under non-filtered and UV-filtered solar-like radiation

Abstract

Silver phosphate is a promising photocatalyst since its energy band gap is situated in the visible range (Eg≈2.4eV), thus this material is a potential candidate for replacing titania which is photoactive only under UV. However, Ag3PO4 suffers of photocorrosion and therefore composites should be prepared to limit this detrimental effect. In this work, pure Ag3PO4 and its composites with AgI, TiO2, and hydroxyapatite were prepared by using various methods. The photoactivity of the materials was evaluated by their ability to decolorize methylene blue and to mineralize phenol under non-filtered and UV-filtered artificial solar-like radiation. The use of UV cut-off filter enhanced the photocatalytic activity of pure silver phosphate by limiting the photocorrosion of silver(I) into Ag°. For composites with AgI and TiO2, despite their lower photoactivity compared to pure Ag3PO4, the efficiency in mineralization of phenol after repeated run is stabilized by using UV cut-off filter. On the other hand, the photocatalytic efficiency of Ag3PO4 composites containing hydroxyapatite remained low mainly due to high absorption properties of hydroxyapatite. The photoactive samples showed excellent photoinduced antimicrobial properties where Gram-negative E. coli was more susceptible to photocatalytic deactivation than Gram-positive S. aureus (MRSA).