First-Principle Modeling of SOx Poisoning in SSZ-13

We use ab-initio molecular dynamics to probe the sulfur deactivation of Cu-SSZ-13 during NO_x NH₃-SCR and find that molecular SO₂, SO₃, and H₂SO₄ are not responsible.  Ab-initio thermodynamics reveal that intermediates (NH₄)₂SO₄ and (NH₄)HSO₄ form with favorable free energies over a range of conditions and are the culprits for poisoning.