Photocatalytic Activity of BiTaO4 Nanoparticles for the Degradation of Methyl Orange Under Visible Light

BiTaO4 nanoparticles were successfully synthesized by the gel-combustion method using polyvinyl alcohol and freshly prepared precursor Ta2O5.nH2O. Materials were characterized by x-ray diffraction and transmission electron microscopy (TEM). With an average grain size of 30 nm, the prepared particle was used to investigate the photocatalytic capacity under the visible light irradiation. The photodegradation process of methyl orange occurred following the pseudo-first order reaction mechanism on the surface of the materials. BiTaO4 nanoparticles which calcined at 750°C presented the best catalytic capacity with the highest rate constant to degrade methyl orange about 5.43 × 10−2 mg l−1 min−1. Besides, the intermediates coming from the photocatalytic degradation of methyl orange were evaluated by liquid chromatography coupled with electrospray ionization ion-trap mass spectrometry (LC/MS). The results showed that the intermediates of degradation reactions of methyl orange were not more toxic than the initial methyl orange. BiTaO4 nanoparticles can mineralize the methyl orange after 60 min of illumination.