Catalysts of Co1.5Mg1.5/Al0.9Ti0.1O and Co1.5Mg1.5/AlO were successfully prepared by calcinations of corresponding hydrotalcite-like compounds at 800℃ for 4 hr.The derived oxides were of spinel phase and a small quantity of Ti substitution did not change the crystal purity.Their catalytic performance for the NO storage/decomposition was investigated.Ti incorporation enhanced the NO decomposition activity while has an opposite effect on the storage capacity of catalyst.In situ FT-IR spectra of the catalysts showed that the final adsorption species on the catalysts was coordinated nitrates/nitrites.In addition,NO storage/decomposition mechanism has been discussed on the basis of these observations.