Synthesis and characterization of calcium-doped lanthanum manganite nanowires as a photocatalyst for degradation of methylene blue solution under visible light irradiation

Abstract

Calcium-doped lanthanum manganite (LCMO) powder was synthesized via hydrothermal method. The structural, morphological and optical properties of the resulting powder was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductively coupled plasma-atomic emission spectroscopy (ICP-AES spectrometer), field emission scanning electron microscopy (FESEM) and UV-Vis spectroscopy (UV-Vis). The XRD results showed the existence of only one crystalline phase. FESEM image indicates that the LCMO sample has nanowire structure with an average diameter of ~125 nm. The band gap energy of the sample was about 2.13 eV. The as-prepared nanowires showed sufficient visible-light photocatalytic activity for the water treatment from dyes and toxic organic materials. The photodegradation efficiency for decolourizing methylene blue solution (7 ppm) by LCMO nanowires (0.07g l-1), after 360 min illumination, was about 73% with a reaction rate constant of 0.003 min-1. The six times cycled results suggested the great long-term stability of the photocatalyst.