Tianjin Key Laboratory of Structure and Performance for Functional Molecules, Key Laboratory of Inorganic-Organic Hybrid Functional Material Chemistry, Ministry of Education, College of Chemistry, Tianjin Normal University, Tianjin 300387, P. R. China
Abstract:
Ag3PO4 polyhedrons were synthesized by a facile hydrothermal route using polyethylene glycol-6000 (PEG-6000). The effects of hydrothermal temperature, reaction time, and PEG-6000 dosage on the morphologies and structures of the products were systematically investigated. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible diffuse reflectance spectra (UV-Vis DRS), and photoluminescence (PL) spectra. The hydrothermal temperature and the PEG dosage are key factors in the production of Ag3PO4 polyhedrons with oriented {110} facets. The Ag3PO4 polyhedrons evolve via Ostwald ripening, and exhibit superior visible-light photocatalytic degradation of Rhodamine B (RhB) relative to Ag3PO4 samples without oriented {110} facets and Ag3PO4 nanoparticles prepared by anion-exchange. The reaction rate constant of the Ag3PO4 polyhedrons was 8.3 times that of the Ag3PO4 nanoparticles. Total organic carbon (TOC) analysis and cycling experiments revealed that the polyhedrons have better mineralization efficiency and exhibit good circulation runs. Holes (h+) and hydroxyl radicals (·OH) are confirmed to be the dominant active species in the presence of radical scavengers and in N2-saturated solution. Given the redox potential of the active species and the band structure of Ag3PO4 polyhedron, the separation and migration mechanism of photogenerated electron-hole (e--h+) pairs at the photocatalytic interface was proposed.
