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

Abstract

Perovskites with ABO3 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 LaNiO3 nanocage (assigned as LaNiO3-Cage, with dual cage or cage in cage structure) was successfully synthesized via a facile hydrothermal method for the first time. LaNiO3-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 N2 adsorption/desorption techniques. The inherent morphology-activity relationship was investigated through Temperature-Programmed Reduction with Hydrogen (H2-TPR), Temperature-Programmed Desorption with Oxygen and Carbon monoxide (O2-TPD and CO-TPD), and X-ray Photoelectron Spectroscopy (XPS) methods. LaNiO3-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 LaNiO3-Cage is well correlated with its special morphology structure. The porous double-shelled LaNiO3 nanocage prepared in this work can be used to design other type of catalysts with the similar morphology as novel nanoreactors.