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

Abstract A series of Ag 3 PO 4 and chitosan (CS) nanocomposites (Ag 3 PO 4 /CS) were prepared through in situ growth of Ag 3 PO 4 with different molecular weight chitosan as adsorbent and soft-template. The structure and properties of as-prepared Ag 3 PO 4 /CS nanocomposites were characterized by XRD, FT-IR, FESEM, TEM, XPS, BET and UV–vis/DRS. The visible-light photocatalytic decolorization behavior of Ag 3 PO 4 /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 Ag 3 PO 4 /CS nanocomposites were prepared in the presence of high molecular weight chitosan, Ag 3 PO 4 particles with cubic or rhombic dodecahedron shape and about 200 to 550 nm in diameter were wrapped in chitosan. Meanwhile, when Ag 3 PO 4 /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 Ag 3 PO 4 crystalline grains and connected by chitosan matrix. The special morphology of Ag 3 PO 4 /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.