Microstructure characterization of hydrothermally synthesized PANI/V2O5·nH2O heterojunction photocatalyst for visible light induced photodegradation of organic pollutants and non-absorbing colorless molecules.

Polyaniline intercalated vanadium oxide xerogel (PV) hybrid nanocomposite (NC) with novel structure has been successfully synthesized through a simple hydrothermal route. Detailed structure and microstructure characterization of PV NC is illustrated through Rietveld refinement of XRD data and FESEM/HRTEM images. Both FTIR and XPS spectra confirm the presence of PANI and water molecules within the NC and partial reduction of V5+ to V4+, corroborating with the results of XRD pattern analysis. Core-shell structure of PV NC, where PANI sheath layer acts as a shell covering around V2O5·nH2O crystalline core is confirmed from HRTEM images. Successive morphological changes of PV NC with different reaction time have been revealed from FESEM images. UV-vis spectra also confirm the formation of PV NC. Intercalation of water and PANI layers into V2O5·nH2O layer leads to a structural phase transition from orthorhombic to monoclinic phase due to substantial increase in interplanar spacing of (00l) of orthorhombic V2O5. The photocatalytic property of the as synthesized PV NC has been reported for the first time, with a promising photocatalytic activity for the degradation of organic dye, Rhodamine B (RhB) under visible light irradiation. It is attributed to a synergic effect in between PANI and V2O5·nH2O xerogel. The photocatalyst also shows remarkable real visible light photocatalytic activity with non-absorbing colorless test molecules like phenol and antibiotic kanamycin.