A chemical bath deposition route to facet-controlled Ag₃PO₄ thin films with improved visible light photocatalytic activity

A facile, economic, and reproducible chemical bath deposition (CBD) method is developed for the fabrication of facet-controlled Ag₃PO₄ thin films with enhanced visible light photocatalytic activity. The fine-control of bath temperature, precursor, complexing agent, substrate, and solution pH is fairly crucial in preparing the facet-selective thin film of Ag₃PO₄ nanocrystal. The change of precursor from silver nitrate to silver acetate makes possible the tailoring of the crystal shape of Ag₃PO₄ from cube to rhombic dodecahedron and also the bandgap tuning of the deposited films. The control of [Ag⁺]/[phosphate] ratio enables to maximize the loading amount of Ag₃PO₄ crystals per the unit area of the deposited film. All the fabricated Ag₃PO₄ thin films show high photocatalytic activity for visible light-induced degradation of organic molecules, which can be optimized by tailoring the crystal shape of the deposited crystals. This CBD method is also useful in preparing the facet-controlled hybrid film of Ag₃PO₄-ZnO photocatalyst. The present study clearly demonstrates the usefulness of the present CBD method for fabricating facet-controlled thin films of metal oxosalt and its nanohybrid.