Oxygen absorption and emission material, catalyst, exhaust gas purification system, and exhaust gas treatment method

摘要

The problem to be solved in the present invention is to provide a three-way catalyst capable of reducing the amount of oxygen absorption and emission of an oxygen adsorbent emission material made up of an HC zirconia based composite oxide which has improved HC and NOx purification performance.And, in order to solve the problem, an oxygen absorbing material having a Celia zirconia composite oxide material containing Gd2O3 of 0.1 mol% or more and 20 mol% or less, and an ion conductivity of 400 ° C. or more is 2 × 10 − 5 S \/ cm or more.In addition, the molar ratio of cerium and zirconium in cerium \/ (cerium + zirconium) is 0.2 or more, 0.6 or less, oxygen absorption rate (OSC rate). Delta. T50 is 20.0 seconds or more, or the oxygen absorption and discharge amount (OSC amount) is 300. Mu.o.o.g\/g An oxygen absorbing and releasing material having characteristics such as above was obtained.Further, by applying the oxygen absorbing and releasing material to the catalyst, the exhaust gas can be cleaned in accordance with the running state, and the catalyst having a high purification performance of the noble metal can be obtained.In particular, it is possible to obtain an automobile exhaust gas purification system superior to CO, NOx and HC purification.