Cubic hematite directly anchored with nanoscale gold for enhanced photocatalysis under visible light

This paper reports the facile synthesis of amine-functionalized cubic hematite (Fe2O3) via hydrothermal reaction between Fe3+ and diamine ligand. The cubic Fe2O3 was directly anchored with negative Au seeds ( < 10 nm), which were grown into large gold nanoparticles (GNPs) using an ascorbic reducing agent. The resulting cubic Fe2O3@GNPs exhibited enhanced photocatalytic activity in the degradation of methylene blue (MB) and methyl orange (MO) dyes under visible light. The photocatalytic activity of cubic Fe2O3@GNPs was optimized by adjusting the size of GNPs and inter-particle distance between them, which were favorable for visible light absorption and separation of electro-hole pairs. Furthermore, the cubic Fe2O3@GNPs exhibited higher photocatalytic activity to the cationic MB dye than the anionic MO dye, due to its adsorption-assisted photocatalytic degradation of organic dyes. The hydrothermal synthetic route is very effective to prepare metal oxide photocatalyst with surface functionality and unique cubic shape.