Sulfur dioxide-resistant platinum-based intermetallic nanocatalysts encaged by porous nitrogen-doped carbon for oxygen reduction reaction

SO 2 , one of the considerable air pollutants, exhibits a stronger binding affinity with Pt when compared to O 2 , thereby inducing irreversible degradation of the Oxygen Reduction Reaction (ORR) catalyzed by Pt-based catalysts. Despite this detrimental phenomenon, scarce investigations have delved into the realm of contaminant-tolerant catalysts, and so far, no effective SO 2 -tolerant catalysts have been proposed. To meet this challenge, we designed and synthesized a core–shell structure catalyst equipped with a dual protection mechanism. This was achieved through the in-situ polymerization of aniline monomers, concomitantly reducing Pt 2+ . The resulting shell effectively hinders the transmission of SO 2 to the active sites of Pt, while permitting the unimpeded transmission of O 2 . Simultaneously, the intermetallic core inhibits the adsorption of SO 2 . Therefore, this catalyst exhibits exemplary ORR activity coupled with exceptional resistance to SO 2 resistance. In particular, the PtFe@FeNC/C-10 catalyst, optimized in terms of the quantity of added aniline, demonstrates a mass activity 1.84 times greater and a specific activity 4.03 times higher than that of commercial Pt/C catalysts. Following exposure to SO 2 -induced poisoning, the E 1/2 value of the PtFe@FeNC/C-10 catalyst undergoes a decrease of only 51.7 mV, lower than that observed for the commercial Pt/C catalyst (92.0 mV). Moreover, the results of an accelerated durability test affirm the superior stability of PtFe@FeNC/C-10 in comparison to commercial Pt/C. This stability advantage is attributed to the protective carbon shell, which effectively prevents the detachment and agglomeration of Pt nanoparticles .