Catalyst, production method thereof, NOx occlusion method, and NOx occlusion reduction method

摘要

PROBLEM TO BE SOLVED: To obtain a composite material excellent in the ability to sorb NOx contained in e.g. an exhaust from an automobile, a production method therefor, to obtain a catalyst excellent in the ability to sorb and reduce NOx and a production method therefor, and to provide an NOx sorption and reduction method. SOLUTION: The method for producing the composite material comprises: the step of effecting the gelation of a solution containing a first compound containing at least one member selected from the group consisting of alkali metals and alkaline earth metals, a second compound containing at least one member selected from the group consisting of group 3 elements, group 4 elements, and transition metal elements, and a third compound having polydentate ligands and the step of firing the obtained gel to obtain the objective composite material.