ZIF-67-derived hollow nanocages with layered double oxides shell as high-Efficiency catalysts for CO oxidation

摘要

Constructing non-precious hybrid metal oxides with specific morphology as cost-effective and highly efficient catalysts is a promising way for the automotive exhaust purification. In this work, we report a facile strategy for the fabrication of a unique hollow Co-Ni layered double oxides (HLDO) nanocages by using zeolitic imidazole frameworks (ZIFs) as template. The synthesis of intermediate core-shell and hollow Co-Ni layered double hydroxides (HLDH) nanoflakes as well as the corresponding Co-Ni oxides products were successfully controlled, and the formation process was also explained. Among ZIF-67-derived oxides, HLDO exhibits excellent catalytic activities (complete conversion of CO into CO2 at 118 degrees C) and long-term stability for CO oxidation. The remarkable catalytic activities of HLDO can be attributed to high surface area (258 m(2) g(-1)) inherited from the HLDH, which could provide more active sites for CO oxidation. In addition, active oxygen species indicated by the O 1 s XPS spectrum and improved synergistic effect between NiO and (CoO4)-O-3 reflected by H-2-TPR, further explain the enhanced performance of the HLDO catalysts. The presented strategy for controlled design and synthesis of hollow multicomponent metal oxides will provide prospects in developing highly effective catalysts. (C) 2018 Elsevier B.V. All rights reserved.