摘要 |
A method of treating a hollandite compound to improve its adsorption of nitrogen monoxide, which comprises subjecting a hollandite compound having a hollandite-type crystal structure and represented by a chemical formula AxMyN8-yO16, wherein A is an alkali metal or an alkaline earth metal K, Na, Rb or Ca, M is a bivalent or trivalent metal element Fe, Ga, Zn, In, Cr, Co, Mg, Al or Ni, N is a tetravalent metal element Sn or Ti, 0<x<=2 and 0<y<=2, to a heat treatment in a stream of an oxygen-nitrogen mixture having oxygen gas and nitrogen gas mixed in a volume ratio of 3:97 to 50:50, at a temperature of from 50 to 1,500° C. for from 5 minutes to 1 hour.
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