Assembly of Ag3PO4 nanoparticles on two-dimensional Ag2S sheets as visible-light-driven photocatalysts

Abstract

Ag₃PO₄ has been proven to be a promising catalyst with superior activity compared to other existing visible-light-driven photocatalysts. In this work, Ag₃PO₄ nanoparticles were deposited on the surface of two-dimensional Ag₂S sheets by an in situ synthesis strategy. The microstructure, composition, and performance of the resulting Ag₃PO₄/Ag₂S composites could be tailored by surface-functioned Ag₂S sheets. The composite reached optimum performance when the molar ratio of Ag₂S to Ag₃PO₄ was 0.31, showing a 2-fold enhancement in the degradation rate in comparison to pure Ag₃PO₄. Efficient separation of photogenerated electron–hole pairs was achieved through a Z-scheme system in which Ag particles served as the center for the combination of electrons at the conduction band of Ag₃PO₄ and holes at the valence band of Ag₂S. In addition to the matched band structure of Ag₂S and Ag₃PO₄, the monodispersed Ag₃PO₄ nanoparticles were efficient in light harvesting due to the presence of Ag₂S. The advantageous interface effect produced by Ag₂S sheets and nano-sized Ag₃PO₄ nanoparticles also contributed to the improvement in photocatalytic activity.