Shape effects of goethite particles on their photocatalytic activity in the decomposition of acetaldehyde

Abstract

The relationship between the photocatalytic activity of goethite (α-FeOOH) and the shape of its particles was investigated. Goethite particles with various morphologies (rod-like, array-like, and pancake-like) were synthesized through the hydrolysis of a ferric nitrate solution or the oxidation of Fe(OH)₂. All the particles synthesized consisted of {110} and {021} facets. The photocatalytic activities of the different samples were examined for the decomposition of acetaldehyde under irradiation. It was found that the photocatalytic activity of goethite is affected by both the shape and the specific surface area of its particles. Further investigation of the effects of the particle shape indicated that the photocatalytic activity of the {021} facets is higher than that of the {110} facets of goethite. The goethite particles (short rod-like and pancake-like particles), therefore, exhibited higher photocatalytic activities than other particle types (long rod-like and array-like particles) owing to the greater {021} facets.