Photocatalytic and semiconducting performance of La modified M-type lead hexaferrite

摘要

La0.2Pb0.7Fe12O19 (LaPbM), a traditional M-type hexaferrite with permanent magnets, was revealed to be a semiconductor by optical spectroscopy. The direct and indirect band gap energies were determined to be 1.70 eV and 0.72 eV, respectively. The Raman spectrum with nine phonon lines are indicative characterization of LaPbM and clearly distinguishes from that of alpha-Fe2O3 and gamma-Fe2O3. Another type of expression for the semiconductor characterization of LaPbM is its photocatalytic activity upon degradation of Methylene Blue (MB) under visible light illumination. Gradually, with an increase in the duration of photodegradation reaction, the color of the MB solution changes from deep blue to pale white and the optical absorption coefficient decreases rapidly. The degradation duration was cut in half when graphen@La0.2Pb0.7Fe12O19 was used as the photocatalytic system. This structure reduced charge recombination and thus enhanced the reactivity. Graphene greatly improves the degradation rate and efficiency of LaPbM through electron transfer. These results provide a new insight into the high performance of visible-light responsive photocatalysis of LaPbM and facilitates its application in environmental protection issues.