Morphology-controlled fabrication of Ag3PO4/chitosan nanocomposites with enhanced visible-light photocatalytic performance using different molecular weight chitosan

A series of Ag3PO4 and chitosan (CS) nanocomposites (Ag3PO4/CS) were prepared through in situ growth of Ag3PO4 with different molecular weight chitosan as adsorbent and soft-template. The structure and properties of as-prepared Ag3PO4/CS nanocomposites were characterized by XRD, FT-IR, FESEM, TEM, XPS, BET and UV-vis/DRS. The visible-light photocatalytic decolorization behavior of Ag3PO4/CS nanocomposites was investigated using methyl orange as a model pollutant. It was found that the morphology and photocatalytic decolorization activity of the nanocomposites significantly depended on the molecular weight of chitosan. The decolorization of methyl orange was ascribed to the synergistic effect of photocatalysis and adsorption. When Ag3PO4/CS nano composites were prepared in the presence of high molecular weight chitosan, Ag3PO4 particles with cubic or rhombic dodecahedron shape and about 200 to 550 nm in diameter were wrapped in chitosan. Meanwhile, when Ag3PO4/CS nanocomposites were fabricated using low molecular weight chitosan as soft-template, 150-400 nm flower-like spheres were obtained which were aggregated by a large number of nanoscale Ag3PO4 crystalline grains and connected by chitosan matrix. The special morphology of Ag3PO4/CS nanocomposites greatly increased the active surface area and the photocatalytic performance. The results in this study suggested that semiconductor photocatalysts with novel morphology and enhanced photocatalytic ability could be fabricated by using different molecular weight chitosan as soft-template. (C) 2016 Elsevier B.V. All rights reserved.