Exhaust Gas Cleaning Catalyst, Exhaust Gas Cleaning Device, and System Comprising Internal Combustion Engine

摘要

The invention makes use of an exhaust gas catalyst, comprising an active component comprising at least one type of metal from noble metals and transition metals; NOx-absorbing material for absorbing and releasing nitrogen oxides according to the surrounding nitrogen oxide concentration; and compounds represented by A₂O₂SO₄ and/or A₂O₂S (A is a rare earth element).