Shielding the interaction between Pt-d and S-p orbitals through carbon encapsulation

The shielding effect effectively suppresses the chemical adsorption between platinum and sulfur species and hinders the formation of Pt-S bonds. • Electrons transfer from Pt to the carbon encapsulation layer to construct metal-carbon interfacial structures, which endows the catalyst with superior hydrogenation activity in sulfur-containing environments. • Carbon-encapsulated structure enhances the structural stability and sulfur resistance of the catalyst. • Experimental characterizations combined with DFT calculations elucidate the underlying reaction mechanism. The presence of sulfur-containing impurities in industrial feedstocks leads to the rapid deactivation of metal-based catalysts, which originates from the specific recognition between the d orbitals of metallic active sites and the p orbitals of sulfur. In this work, a carbon-encapsulation catalyst strategy was employed to shield this specific d–p orbital recognition effect. The Pt-base catalyst showed a sharp 92.28% loss in activity after sulfur poisoning, whereas the carbon-encapsulated catalyst maintained high efficiency and stability, sustaining a reaction rate of 83.41 min –1 even at high mercaptan concentrations (7945 ppm). Moreover, it exhibited excellent reusability with negligible deactivation after five cycles. Characterization and density functional theory (DFT) calculations revealed that the carbon shell serves as “armor” for Pt active sites, physically isolating them from sulfur impurities and suppressing the hybridization between Pt nanoparticles (Pt NPs) and the S 2p orbitals. Meanwhile, Pt nanoparticles induce electron transfer to the carbon layer, converting it into a conductive “metallic carbon” that enhances hydrogenation activity. This work provides new insights into the anti-sulfur poisoning mechanism of catalytic hydrogenation. Download: Download high-res image (255KB) Download: Download full-size image