Hematite Photocatalysis: Dechlorination of 2,6-Dichloroindophenol and Oxidation of Water

We report photocatalytic studies employing colloids of pure hematite (α-Fe2O3) and hematite loaded with 1 and 5 wt % platinum, respectively. The kinetics of the dechlorination of the redox indicator 2,6-dichloroindophenol (DCIP) have been studied in aqueous colloidal suspensions of hematite at pH 7. At the same time, α-Fe2O3 carries out the photooxidation of water. The formation of hydroxyl radicals and of H2O2 has been investigated employing coumarin and p-hydroxyphenylacetic acid as reagents, respectively. With an increased amount of platinum on the colloidal surface, an enhanced photonic efficiency of the dye reduction is observed.