NOX OCCLUDING MATERIAL AND NOX TREATING DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a material capable of transiently occluding the NOx in a high-oxygen exhaust gas of a diesel engine, etc., or occluding and removing the NOx liberated into the atmosphere and to provide an NOx treating device using the same. SOLUTION: The NOx occluding material of this example is a hollandite- structure multiple oxide shown by K3.6 Zn1.8 Sn6.2 O16 , using K as an alkali metal, with Zn and Sn as the essential metallic elements and for which X=1.8 and Y=3.6. The multiple oxide is obtained by dripping an aq. soln. of zinc nitrate and potassium nitrate gradually into a soln. of tetra-iso-propoxytin in isopropanol to hydrolyze the nitrates, evaporating the mixed soln. to dryness at 100 deg.C, crushing the dried material in an alumina mortar to obtain a raw composition and heat-treating the composition at 800 deg.C for 6hr in the atmosphere. The multiple oxide has a large surface area and occludes NOx effectively even at a high temp.