Influence of secondary oxide phases in enhancing the photocatalytic properties of alkaline earth elements doped LaFeO3 nanocomposites

Abstract

An improvement in the photocatalytic activity of lanthanum ferrite was attempted by doping individual alkaline earth elements (Ba, Ca and Sr) in its La site and Mg in Fe site to get the desired energy band characteristics. All doped compositions of LaFeO3 were synthesised by sol-gel method. Structural studies show the formation of secondary oxide phases when calcined at 800 °C and phase pure compounds when calcined at 1100 °C. Optical studies reveal the capability of these perovskites to be visible light active and indicate that the bandgaps become narrower after doping alkaline earth elements. Photocatalytic activity was tested through Congo Red (CR) dye degradation studies and hydrogen evolution through water splitting. The results indicate that Mg doped LaFeO3 composite which was obtained after the calcination at 800 °C shows higher hydrogen evolution rate and the highest rate of Congo red (CR) dye degradation among all synthesised compositions of undoped and doped LaFeO3 under natural Xenon lamp irradiation. The possible mechanism of the photocatalytic activity is also proposed in this study.