Baize-like CeO₂and NiO/CeO₂nanorod catalysts prepared by dealloying for CO oxidation

Abstract

Baize-like monolithic CeO 2 and NiO/CeO 2 nanorod catalysts were prepared by combined dealloying and calcination and the catalytic activities were evaluated using CO catalytic oxidation. The CeO 2 catalysts were composed of nanorods and exhibited a three-dimensional supporting structure with pores. After introduction of NiO, dispersed NiO nanosheets and nanoparticles were supported on the surface of CeO 2 nanorods and they were not well-crystallined due to CeO 2 inhibiting the NiO crystallization. The Raman and x-ray photoelectron spectroscopy analyses revealed that the introduction of NiO species into CeO 2 generated more coordinate unsaturated Ni atoms, oxygen vacancies, defects and active sites for CO catalytic reactions. The reaction activation energy of NiO/CeO 2 nanorod catalyst prepared from the Al 83 Ce 10 Ni 7 precursor alloy was just 31.2 kJ mol −1 and the CO conversion can reach up to 97% at 240 °C, which was superior to that of pure CeO 2 and nanoporous NiO. The enhanced catalytic activity of baize-like NiO/CeO 2 nanorods can be attributed to the strong synergistic effects between finely dispersed NiO species and surface oxygen vacancies in CeO 2 nanorods.