Visible light photo-Fenton catalytic properties of starch functionalized iron oxyhydroxide nanocomposites

Abstract The photocatalytic properties of nanocomposites of akageneite and goethite have not been explored in literature. The present communication uses a green synthesis protocol to produce rod-shaped akageneite/goethite nanocomposites. The functionalization of these nanocomposites by starch changed their shapes to rice grain-like, improved the hydrophilicity of the surfaces of the nanoparticles, blue-shifted the Fe-O bond FTIR peak, and also altered their band structure to make them better visible light photocatalysts. The Mott-Schottky plots of (both starch functionalized and non-functionalized) the nanocomposites exhibited positive and negative slope parts, confirming the formation of a p-n heterojunction. Starch functionalization changed not only the band gap but also the band positions and the relative band alignments of the components making the nanocomposites. Degradation of p-nitrophenol (PNP) and methyl orange (MO) were efficiently photocatalyzed by these nanocomposites under visible light photo-Fenton conditions. The degradation of PNP and MO followed zero-order kinetics under photo-Fenton conditions. Starch functionalization of the nanocomposite led to significant improvement in the photo-Fenton activity of this catalyst in comparison to that exhibited by the non-functionalized counterpart. The photo-Fenton activities of both nanocomposites for PNP and MO degradation are among the best reported in literature till date.