On-line measurement of photocatalytic activity of powdered samples

Abstract

A method for on-line measurement of photocatalytic activity of powdered samples by UV-Vis spectrometry is demonstrated. It enables photocatalytic reaction to be monitored directly in the cuvette which also serves as photocatalytic reactor. The cuvette is placed inside a double beam UV-Vis spectrometer and photocatalytic reaction is driven by LED diode mounted on homemade cuvette holder housing. Diodes can be easily changed, enable photocatalytic reaction to be performed under light of various wavelengths which is beneficial when evaluating visible-light photocatalytic activity. Another advantage of the method presented lies in the simultaneous degradation of model dye solution and monitoring of reaction kinetics, which avoid sampling during the photocatalytic reaction. Measurement of photocatalytic activity is demonstrated on degradation reaction of Methylene blue 2B as the model dye by Zn2TiO4 powder under the UV (λ ∼ 365 nm), and the visible light (λ ∼ 400 nm) and (λ ∼ 425 nm) irradiation.