摘要 |
PROBLEM TO BE SOLVED: To suppress the migration of an alkali metal and to enhance the permanence of NOx removing power. SOLUTION: An NOx occluding material has a core-shell structure comprising a core body comprising an alkali metal and a shell layer coating the periphery of the core body, wherein the shell layer contains an element selected from the alkaline earth metals, the rare earth elements, Mn, Fe, Co and Ni. Since the shell layer is in the solid state at high temperature, the migration of the alkali metal is regulated by the shell layer. |