Impacts of CuO x additive on the CO oxidation activity and related surface and bulk properties of a NANO-CeO2 Catalyst

Abstract

Nano-particle, pure and CuO x -modified, fluorite-structured cubic-CeO2 were successfully synthesized with surface areas near 240 m2/g applying a microemulsion method with mixed templating surfactants (viz. DDAB and Brij®35). Following calcination at 400–800 °C, the products were characterized by X-ray powder diffractometry, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy, and, then, tested as catalysts for methylbutynol decomposition and CO oxidation in the gas phase. Results obtained showed the pure and CuO x -modified cerias to exhibit comparable activities towards the alcohol decomposition into acetone and acetylene, but the modified ceria exhibited considerably higher activity towards the CO oxidation than the pure one. The calcination product of CuO x -modified ceria at 800 °C was capable of lowering the light-off temperature of the CO oxidation from 300 °C (on the pure) down to 70 °C. Surface chemical consequences of the CuO x -modification, viz. increasing the Ce(III)/Ce(IV) atomic ratio, as well as the establishment of Cu(I) and Cu(II) sites, have been allocated the responsibility of the observed upsurge of the CO oxidation activity.