The three-way catalytic converter is a conventional solution of gasoline exhaust after-treatment. As its operation temperature ranges from 400 to 1100 deg.C, material with adequate expansion gap.For design with enough substrate iso-strength, classical intumescent mat KY100 is a good choice. While ultra-thin-wall substrate is used, non-intumescent mat CNE and PNE.Gasoline exhaust after-treatment system should have GPF to meet the requirement of China VI stage standard. The huge back-pressure of GPF challenges the total life cycle performance of support mat. Polycrystalline non-intumescent mat PNE could take on this task.