Double-shelled hollow LaNiO3 nanocage as nanoreactors with remarkable catalytic performance: Illustrating the special morphology and performance relationship

Abstract Perovskites with ABO 3 structure are the potential catalysts to replace the noble metals used in environmental catalysis, e.g. CO oxidation, volatile organic compounds (VOCs) and soot combustion. Herein, a novel double-shelled porous perovskite-type LaNiO 3 nanocage (assigned as LaNiO 3 -Cage, with dual cage or cage in cage structure) was successfully synthesized via a facile hydrothermal method for the first time. LaNiO 3 -Cage displayed superior activity and stability for CO oxidation. The morphology and structure properties of the samples were confirmed by Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), High-angle annular dark-field scanning transmission electron microscope (HAADF-STEM), Elemental mapping, Powder X-ray Diffraction (PXRD) and N 2 adsorption/desorption techniques. The inherent morphology-activity relationship was investigated through Temperature-Programmed Reduction with Hydrogen (H 2 -TPR), Temperature-Programmed Desorption with Oxygen and Carbon monoxide (O 2 -TPD and CO-TPD), and X-ray Photoelectron Spectroscopy (XPS) methods. LaNiO 3 -Cage showed superior catalytic performance among all the comparison samples (with lowest Ea, highest reaction activity, rate and TOF value) which should be ascribed to its special double-shelled porous nanocage structure (main factors) as well as larger surface areas and more active surface oxygen species. It should be noted that the outstanding catalytic performance of LaNiO 3 -Cage is well correlated with its special morphology structure. The porous double-shelled LaNiO 3 nanocage prepared in this work can be used to design other type of catalysts with the similar morphology as novel nanoreactors.