Novel nanorod Au/Sm2O3 catalyst synthesized by dealloying combined with calcination for low-temperature CO oxidation

Abstract

A Au/Sm2O3 composite was designed and prepared by a simple combination of dealloying a melt-spun Al-Sm-Au precursor alloy in a NaOH solution with calcination. SEM and TEM results revealed that the composite has a three-dimensional porous nanorod skeleton structure; Au nanoparticles were supported in situ and were highly dispersed on the surface of the Sm2O3 nanorods. The experimental results in an anaerobic environment showed that the Sm2O3 support prepared by dealloying has a strong ability to store/release oxygen. The catalytic activity test results indicated that the dealloyed Al91.5Sm8Au0.5 ribbon calcined at 400 °C (0.5Au/Sm2O3-400 °C) can completely convert CO at 130 °C. The CO conversion was reduced by only 4% after 150 h in the presence of high concentrations of H2O and CO2, exhibiting excellent water resistance and the long-term stability of the catalyst. The analyses revealed that the high catalytic activity was attributable to the porous nanorod skeleton structure of Sm2O3, a high dispersion of Au nanoparticles, increased oxygen vacancies and Auδ+ species, strong interactions between Au and Sm2O3, and the strong ability of the Sm2O3 nanorods to store/release oxygen.