Carbon sphere templated synthesis of LaFeO 3 perovskite and its catalytic performances for RhB oxidation

Carbon sphere was synthesized by hydrothermal method using sucrose as precursor, with particle size and surface properties tuned by hydrothermal time (6–24 h). It was then used as template to prepare LaFeO3 perovskite. X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and N2 physisorption results showed that LaFeO3 with perovskite structure was formed and its crystal system transformed from orthorhombic to cubic with increasing the hydrothermal time of carbon sphere. Compared to the LaFeO3 synthesized without carbon sphere template, the synthesized LaFeO3 perovskite with carbon sphere possessed improved surface area, dispersion and surface chemistry. Room-temperature activity of LaFeO3 for H2O2 decomposition and rodamine B (RhB) oxidation using H2O2 as oxidant was tested, which showed that LaFeO3 is active for RhB oxidation and the best activity is obtained from that prepared with carbon sphere hydrothermally treated for 20 h (denoted as LaFeO3-C20). By comparing the activity of H2O2 decomposition and RhB oxidation, it was inferred that the intermediates of H2O2 decomposition is the active species for RhB oxidation. Long-term stability tests of LaFeO3-C20 for RhB oxidation showed that no activity loss is observable within 6 runs, suggesting that LaFeO3-C20 is highly stable in the reaction.