CO reactive adsorption at low temperature over CuO/CeO2 structured catalytic monolith

CO adsorption on a copper/ceria nanopowder washcoated onto a cordierite monolith has been studied at low temperature by following the time evolution of the outlet concentration of CO and CO2 on nanometric CuO/CeO2 catalyst. The effects of adsorption time length, gas phase composition (H2 or O2 addition), temperature and contact time were investigated. Results showed that the high surface and the large availability of labile oxygen allows CO oxidation and CO2 release even at room temperature. Moreover, tests under transient conditions showed that i) interfacial copper/ceria sites re-oxidation can benefit of oxygen transfer from ceria depending on the operating conditions (O2 partial pressure, temperature, etc.), ii) hydroxyl groups, boosting CO2 production rate, can be formed over the catalyst surface by reaction with molecular H2 at temperature above 80 °C, and iii) several CO and CO2 adsorbed species must be taken into account, covering not only copper but also ceria sites, some of them being spectators in the reaction pathway. Finally a novel strategy for CO removal based on CO trap is proposed.