Nanoporous Ag-CeO₂ ribbons prepared by chemical dealloying and their electrocatalytic properties

A novel and facile strategy for the preparation of a monolithic Ag-CeO ₂ composite is reported. Here, nanoporous Ag-CeO₂ ribbons are successfully prepared through dealloying melt-spun Al_79.5Ag ₂₀Ce_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-CeO ₂ 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.