Characterization of phosphorus poisoning on diesel exhaust gas catalyst components containing oxide and Pt

Abstract

Effects of phosphorus poisoning on the characteristics of powdered exhaust gas catalyst components containing different oxides and platinum were studied. The amount of phosphorus accumulated in the sample during the laboratory-scale ageing procedure varied for the samples with different composition. The phosphorus ageing affected substantially the characteristics of the samples, which could be detected as a decrease in the specific surface area and pore volume and an increase in the average pore size. Large platinum particles and an increase in the washcoat grain-size were observed after the ageings.

Structural changes in air aged and poisoned diesel catalysts

“…The observed structural changes in the treated catalysts are in good agreement with the results of specific surface area measurements (BET theory) of fresh and phosphorus poisoned catalysts carried out at the University of Oulu [14]. BET-results showed remarkable loss of active surface area due to the poisoning treatment.…”

Effect of Na, K, Ca and P-impurities on diesel oxidation catalysts (DOCs)

“…In order to verify if this effect was associated with the impact of the second hydrothermal treatment after the impregnation of the additives, a second hydrothermal calcination at 650ºC was performed to the reference catalyst (Aged -PtPd). The obtained results indeed evidenced that the ageing treatments had an effect on the SSA of this catalyst, which was decreased after treatment, phenomenon also observed by some other authors [21].…”

Biofuel Impact on Diesel Engine After-Treatment: Deactivation Mechanisms and Soot Reactivity

“…Relatively little information is available regarding the potential role of phosphorus, even if phosphorus is reputed to be a sintering agent. At high temperatures (700°C), phosphorus favours the growth of platinum particles and affects platinum structure [24,25]. Phosphorus also interacts with platinum by forming platinum phosphide [26].…”

“…The role that phosphorus plays as a sintering agent has also been highlighted for certain oxides that are commonly found in post-treatment catalysts [24,25]. Phosphorus leads to the sintering of ceria (CeO2), with the formation of cerium phosphate (CePO4).…”