MOF-derived hollow porous Ni/CeO2 octahedron with high efficiency for N2O decomposition

Abstract

A novel material of hollow porous NiO@CeO2 octahedron (HPOC) derived-from cerium-based metal-organic frameworks (MOF) was prepared as a high-performance catalyst for N2O decomposition. Octahedron-shaped cerium-based MOF was successfully synthesized with formic acid as a structure-modulating agent by rational controlling the volume ratio of N,N-dimethylformamide and formic acid at 4:1. The obtained NiO@CeO2-HPOC was systematically characterized to reveal its morphology, structure and surface properties. TEM, SEM and N2 adsorption-desorption isotherms results confirm the well-defined octahedral morphology and hollow porous structures of NiO@CeO2-HPOC. EDS mapping and XRD studies indicate that NiO@CeO2-HPOC hybrid composite exhibits relatively homogeneous Ni dispersion and small NiO size, which comes from the unique coordination bond and porosity of cerium-based MOF precursor. H2-TPR analysis shows that uniform nickel distribution enables the highly dispersed NiO species in NiO@CeO2-HPOC. Furthermore, Raman and XPS results indicate that NiO@CeO2-HPOC possesses large amount of oxygen vacancies. The hollow porous structures, homogeneous Ni dispersion, as well as large amount of oxygen vacancies facilitate the catalytic efficiency. As a result, NiO@CeO2-HPOC exhibits a high catalytic activity and enhanced O2 tolerance for N2O decomposition.