NO-TPSR and CO-NO catalytic reaction on Pt/HM and Pd/HM were studied. There are three kinds of NO adsoption sites. The lower temperature adsoption site is attributed to the metal Pt or Pd, and the two higher temperature adsoption sites are attributed to the basic sites on HM surface. The adsorbed NO undergoes extensive de composition to form N2. N2O and O2 during NO thermal desorption on all catalysts studied. The desorption of N2. N2O and NO on Pt/HM catalyst is easier than that on Pd/HM catalyst. Pt/HM catalytic activity for CO-NO reaction is higher than Pd/HM’s,which is consistant with NO decomposition ability of the catalyst. The dissociation of NO on catalyst is the rate determing step of CO-NO reaction.
