Tuning the interfacial interactions between alumina support and pseudo single atom platinum-tin catalytic sites for heavy naphtha reforming

Abstract

Heavy naphtha reforming, a crucial downstream process in oil refineries for improving the octane number of the gasoline feedstock, requires expensive Pt metal catalysts and it accounts for 60% of the catalyst cost. These conventional Pt nanoparticle sizes range between 1 – 2 nm and thus, only ≈ 80% of the Pt atoms of the particle are available for the catalytic reactions. In this work, we hypothesized that it might be possible to achieve 100% atom utilization if the Pt atoms are distributed as single or pseudo-single atom clusters, where all the atoms are exposed to the reactant molecules and by tuning their Interfacial Interactions. We aimed to significantly reduce the Pt contents by dispersing the active Pt sites as pseudo-single atoms on industrially relevant γ-Al2O3 support. Interfacial Interactions and stability of Pt sites were then tuned by using tin (Sn) as a promoter. These catalysts were then evaluated for heavy naphtha reforming in a fixed-bed reactor. The catalyst with Sn/Pt mole ratio of 1.68 showed excellent performance with aromatics of 83 wt% and research octane number (RON) of ≈ 103. These results indicated our catalyst preparation methodologies and interfacial interaction tuning successfully disperse Pt on the spherical alumina support leading to better atom economy. With 30–50% less Pt content when compared to the industrially used catalyst, made the heavy naphtha reforming process economical and sustainable.