Photocatalytic property of perovskite LaFeO3 synthesized by sol-gel process and vacuum microwave calcination

Perovskite LaFeO 3 nanoparticles with an orthorhombic structure were synthesized by a sol-gel route and subsequent vacuum microwave calcination. The effects of vacuum microwave calcination temperature and duration on the formation of LaFeO 3 single phase were investigated. The use of vacuum microwave calcination can effectively reduce the crystallization time of LaFeO 3 nanoparticles. The synthesized LaFeO 3 nanoparticles have a perfect crystal structure, a single phase composition without any impurity, uniform particle size, and a suitable energy band of ∼1.86   eV. According to the PL spectrum of LaFeO 3 nanoparticles, the recombination rate of photo-generated electrons and holes can be reduced due to the use of vacuum microwave calcination. Furthermore, LaFeO 3 nanoparticles calcined by vacuum microwave calcination have a superior visible photo-catalytic efficiency on organic dye methyl orange and methyl blue, and a higher photodegradation efficiency rate, compared to those calcined by conventional calcination. LaFeO 3 nanoparticles obtained by vacuum microwave calcination at 700   °C for 30   min (sample MW-700-30) exhibits superior photocatalytic efficiency, and the MB and MO dye solution in the presence of LaFeO 3 nanoparticle becomes colorless during 240   min under visible light irradiation. The photodegradation process of MB on the as-synthesized LaFeO 3 follows a pseudo-first-order kinetic process.