Decomposition of methyl orange using C60 fullerene adsorbed on silica gel as a photocatalyst via visible-light induced electron transfer

Abstract Visible-light induced electron transfer reactions of C 60 fullerene adsorbed on silica gel (C 60 /SiO 2 powder) to methyl orange in water have been studied. The C 60 /SiO 2 powder was simply prepared by mixing a toluene solution of the C 60 fullerene with silica gel followed by evaporating the toluene. Irradiation by visible light (>420 nm) of the methyl orange aqueous solution (25 μM) in the presence of the C 60 /SiO 2 powder and ascorbic acid resulted in the decomposition of the methyl orange. These results showed that the degradation conversion reached 96% after a 25-min visible light irradiation. The reaction also occurred by the irradiation of sunlight. The reductive products of methyl orange, N , N -dimethyl- p -phenylenediamine and sulfanilic acid, were ascertained and monitored by liquid chromatography/mass spectrometry (LC/MS). The reaction did not occur in the dark and in the absence of C 60 /SiO 2 or ascorbic acid. The possible mechanism of the reaction is discussed. Furthermore, the C 60 /SiO 2 powder was applied to a continuous flow system for the photodecomposition of methyl orange. C 60 /SiO 2 powder was packed in a glass tube. The methyl orange solution was pumped into the glass tube, and the tube was irradiated by visible light or sunlight. The continuous decomposition of methyl orange was achieved by this method.