In this study, a WO3–multiwalled carbon nanotube nanocomposite has been prepared for the first time by in situ liquid phase process. The prepared nanocomposite was used for photodegradation of dilute solution of naphthalene under visible light irradiation. Based on our results, comparing photocatalytic activity of WO3 nanoparticle with WO3–multiwalled carbon nanotube nanocomposite showed that the photodegradation of naphthalene is negligible by using pure WO3 nanoparticles while, composition of WO3 nanoparticles with multi walled carbon nanotubes could improve significantly their photocatalytic activity under visible light. Due to its high electrical conductivity, carbon nanotube can transfer photogenerated electron on its surface and in this way decreases electron–hole recombination rate and increases photocatalytic activity. After the reaction, the irradiated solution has been analyzed by gas chromatography and mass spectrometry techniques for identification of the naphthalene photodegradation intermediates and products. 1-Naphthol, 1,4-naphthalenedione and 1,2-benzendicarboxilic acid have been determined as intermediates and based on these intermediates a suitable mechanism for photodegradation of naphthalene was suggested.
