Deposition of a very small amount (0.14 wt%) of Cr-Cu onto CeO2 accompanied by thermal aging at 900 degrees C for 25 h resulted in a high catalytic activity for stoichiometric CO-NO reaction. Although the catalyst was superior to Rh/CeO2 with the similar metal loading and thermal aging history, such a high activity could not be obtained by using other metal oxide supports (gamma-Al2O3, TiO2, ZrO2, and CeO2-ZrO2). The active site that consists of Cu+ and Cr3+ embedded onto the CeO2 surface may be formed by thermal aging and its local structure is different from the bulk oxide of CuCrO2. A possible reaction mechanism of CO-NO reaction over the Cr-Cu embedded CeO2 surface was discussed from the results of kinetic analysis, isotopic reaction between (CO)-O-16 and (NO)-O-18 and in situ infrared spectroscopy. It is suggested to involve the dissociative adsorption of NO and subsequent oxygen exchange with the surface in parallel to CO oxidation by the surface oxygen species. (C) 2016 Elsevier B.V. All rights reserved.