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.

A novel and facile strategy for the preparation of a monolithic Ag–CeO₂ composite is reported. Here, nanoporous Ag–CeO₂ ribbons are successfully prepared through dealloying melt-spun Al_79.5Ag₂₀Ce_0.5 alloy in a 5 wt% NaOH aqueous solution, followed by calcining in air. The Ag–CeO₂ ribbons with a homogeneous pore/grain structure are thermally stable up to 973 K because of the formation of Ag cores and CeO₂ shells. Uniform CeO₂ particles with lengths of about 5 nm are dispersedly loaded on the fine Ag grains of the porous structure. The Raman spectra show that a larger number of oxygen vacancies are formed in the CeO₂ nanoparticles with an increase of the calcination temperature. The electrochemical tests reveal that the nanoporous Ag–CeO₂ catalyst exhibits an enhanced activity toward the direct oxidation of sodium borohydride. The superior catalytic activity is attributed to the enhancement of the interfacial interaction between Ag and CeO₂. The present work opens up a novel method to prepare metal–CeO₂ nanocomposites with high catalytic performance and low cost.

A series of Co ₃ O ₄ catalysts modified by Sm were prepared by a combined dealloying and calcination approach, and the catalytic activities were evaluated using CO catalytic oxidation.