A seriesof Fe/activated carbon catalysts were prepared by impregnationof activated carbon with aqueous solution of ferric nitrate and employedin phenol hydroxylation to dihydroxybenzenes using hydrogen peroxideas oxidant. The samples were characterized by thermal analysis, inductivelycoupled plasma atomic emission spectrometry (ICP-AES), N2-adsorption, temperature-programmed oxidation mass spectrometry (TPO-MS),scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-rayphotoelectron spectroscopy (XPS). Part of the ferric (Fe(III)) specieswas reduced to ferrous (Fe(II)) species forming Fe3O4when the Fe/activated carbon catalyst was heated at 400 °Cfor 3 h in air. Fe3O4highly dispersed on activatedcarbon was found to be the active phase for the target reaction. Theappearance of ferrous (Fe(II)) species greatly improved the catalyticactivity. A phenol conversion of 41.3% and a yield of 36.0% to dihydroxybenzeneswere obtained under the following optimal reaction conditions: catalystamount, 0.1 g; reaction temperature, 30 °C; molar ratio of phenol/H2O2, 10.6/9.8; reaction time, 1 h. [ABSTRACT FROM AUTHOR]