Temperature programmed desorption(TPD) was used to study the desorption and decomposition of NO adsorbed on Cu/MgO catalysts. These are two kinds of NO adsorption sites on MgO surface, which are attributed to the basic sites. The basic sites of MgO surface are covered with Cu, therefore there are only one NO adsorption on Cu/MgO catalyst surface except Cu/MgO (1%), which is attributed to metal Cu. The adsorption NO undergoes extensive decomposition to form N~2, N~2O and O~2 during NO thermal desorption on all catalysts. CO-NO activity of catalysts is closely related to their NO decomposition activity. CO-O~2 reaction is easier than CO-NO on all catalysts. The dissociation of NO on catalyst to form N~a and O~a is the rate determing step of CO-NO reaction. N~2O formation dominates at lower temperature during NO reduction, whereas N~2 formation dominates at higher temperature.

Key words: REACTION PROPERTIES, METAL CATALYST, CATALYST, DECOMPOSITION