PNNL

Abstract

Carbon supported ?-Fe2O3 nanoparticle (?-Fe2O3/C) possessing both superparamagnetism and activating molecular oxygen properties were prepared by an ammonia-assisted precipitation method. It could catalyze the selective oxidation of various benzyl alcohols with air as oxidant source, and could be easily recycled with an external magnet separation. The correlation between the intrinsic properties of ?-Fe2O3 nanoparticles and the catalytic performance was investigated with a series of characterizations. It shows that the oxidation state of ?-Fe2O3 nanoparticles were facile to be changed, which should be related to its inverse spinel type crystal structure with vacant cation sites. These ?-Fe2O3 nanoparticles should be the active sites and responsible for the high activity of ?-Fe2O3/C in the air oxidation of alcohols. The formation of ?-Fe2O3 nanoparticle was controlled by precipitation agent and carbon support. Using ammonia ethanol solution as precipitation agent, the hydrolysis rate of iron species could be decreased. The surface functional groups of carbon support could act as chelating sites for iron species, controlling the nucleation and growth of the ?-Fe2O3 nanoparticles in the preparation process. Dr. Xiang Wang gratefully acknowledges the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division for the support of this work.