Peroxydisulfate activation by LaNiO3 nanoparticles with different morphologies for the degradation of organic pollutants

A series of LaNiO 3 perovskite nanoparticles with different morphologies, such as spheres, rods and cubes, were prepared through co-precipitation and hydrothermal methods, and used as the catalysts for peroxydisulfate (PDS) activation. The physical and chemical characterization of LaNiO 3 perovskites was performed, including X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen isotherm absorption (BET), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). The LaNiO 3 with different shapes showed different activities in Acid Orange 7 (AO7) degradation. Sphere-like LaNiO 3 exhibited the highest catalytic activity, which is probably due to the largest specific surface area, higher proportion of reductive Ni 2+ and the higher electron transfer ability. The radical scavenging experiments and electron paramagnetic resonance (EPR) revealed the production of massive sulfate radicals (SO 4 •− ) and hydroxyl radicals ( • OH) during the oxidation. Finally, the possible mechanisms of PDS activation and AO7 degradation were proposed. The prepared LaNiO 3 perovskites also showed excellent reusability and stability. Three LaNiO 3 perovskites with different morphologies were synthesized. Sphere-like LaNiO 3 exhibited the highest catalytic activity for activating PDS. Produced • OH and SO 4 •− were main active species in the reaction system. The mechanism of AO7 degradation reaction in the system was proposed. LaNiO 3 can be reused for multiple cycles to activate PDS for AO7 degradation.