Boosted low-temperature C3H8 oxidation and sulfur resistance of Pt/CeO2 via post Co3(PO4)2 modification: Synergy of interfacial electronic modulation and phosphate-derived acidity

The widely presented industrial light alkanes (LAs) have posed significant hazards to the environment and human health; however, the efficacious catalytic purification of LAs is still greatly suffered from their strong chemical stability and catalyst deactivation due to the presence of sulfur-containing impurity in practical exhausts. Herein, cobalt phosphate (Co 3 (PO 4 ) 2 )-modified Pt/CeO 2 catalysts (Pt/CeO 2 - x CP) with boosted activity and sulfur resistance were rationally engineered. Results revealed that Pt/CeO 2 -0.2CP shows the highest C 3 H 8 oxidation activity with 90 % of which oxidized at 260 °C and apparent activation energy ( E a ) of 84.39 kJ∙mol −1 , obviously lower than that of Pt/CeO 2 . Remarkably, the activity of Pt/CeO 2 -0.2CP is well-maintained in 24 h of successive operation with the co-existence of 250 H 2 S, while over 20 % of C 3 H 8 conversion reduction can be found over Pt/CeO 2 due to the deactivation of Pt 4+ active sites by surface sulfation. The Co 3 (PO 4 ) 2 -Pt interface promotes the electron transfer from Pt δ+ to phosphorus component and weakens the Pt-O-Ce bond, thereby generating more highly active Pt 4+ sites and oxygen vacancy, polarizing the electron cloud around the C-H bond and oxygen molecules and promoting C 3 H 8 oxidation. Meanwhile, the Co 3 (PO 4 ) 2 modification optimizes the surface acidity of Pt/CeO 2 -CP, effectively weakens the adsorption and oxidation of H 2 S, and maintains the formation and consumption of high active oxygen species, resulting in strong sulfur resistance. This work provides important insights for the rational design of efficient sulfur-tolerant catalysts towards LAs purification under harsh conditions.