Deactivation of phosphorus-poisoned Pd/SSZ-13 for the passive adsorption of NOx

Automotive catalysts can be exposed to various poisonous substances that cause physical or chemical deactivation. One of such poisons is phosphorous, which originates from lubricant oils. This study focuses on the phosphorus deactivation Pd/SSZ-13 used as a passive NOx adsorber (PNA). A clear caused by was observed, and it increased increasing content phosphorous. It concluded phosphorous both evident XPS analysis, where presence pentoxide (P2O5) causes whereas metaphosphate (PO3-) phosphate (PO43-) Also, shown metaphosphates become dominant species at higher P concentrations. Lesser amounts O2 were released in P-poisoned Pd/SSZ-13, found oxygen TPD when concentration, due more PO3- species. Furthermore, XRD 27Al NMR analyses revealed also interacted with alumina zeolite framework forming Al-O-P species; this supported SEM-EDX, there overlap Al Pd spectra. DRIFTS analysis showed OH groups contact structure became contaminated Pd/SSZ-13. that, during multiple cycles, PNA capacity decreased for phosphorus-poisoned samples. transformation P2O5, blocking, PO3-, interacts chemically palladium