Sodium-promoted NO adsorption under lean conditions over Cu/TiO2 catalysts

A dramatic improvement of Cu/TiO2 as NO adsorbent was achieved by the addition of Na. It was observed that the improvement in NO adsorption was accompanied by the appearance of nitrate and nitrite species on the surface of the Na/Cu/TiO2 adsorbent. The presence of copper leads to an in situ oxidation of NO to NO2, which facilitates the formation and adsorption of nitrite and nitrates species. The presence of sodium results in less reducible copper species.