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

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 Al79.5Ag20Ce0.5 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.