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

A series of LaNiO3 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 LaNiO3 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 LaNiO3 with different shapes showed different activities in Acid Orange 7 (AO7) degradation. Sphere-like LaNiO3 exhibited the highest catalytic activity, which is probably due to the largest specific surface area, higher proportion of reductive Ni2+ and the higher electron transfer ability. The radical scavenging experiments and electron paramagnetic resonance (EPR) revealed the production of massive sulfate radicals (SO4•−) and hydroxyl radicals (•OH) during the oxidation. Finally, the possible mechanisms of PDS activation and AO7 degradation were proposed. The prepared LaNiO3 perovskites also showed excellent reusability and stability. HIGHLIGHTS Three LaNiO3 perovskites with different morphologies were synthesized.; Sphere-like LaNiO3 exhibited the highest catalytic activity for activating PDS.; Produced •OH and SO4•− were main active species in the reaction system.; The mechanism of AO7 degradation reaction in the system was proposed.; LaNiO3 can be reused for multiple cycles to activate PDS for AO7 degradation.