Revealing sulfur-resistant Pt–CeO2 interfacial sites for water–gas shift catalysts toward waste-to-hydrogen

Abstract

The effects of introducing various transition (Nb, Mo, W, and Re) and nontransition (Al, Ga, Sn, and Pb) metal promoters into Pt/CeO₂ catalysts on sulfur tolerance, catalytic activity, and regeneration behavior during waste-to-hydrogen conversion processes were investigated. Although the impact of promoter addition depended on the metal species, all promoters interacted with both the active metal and the CeO₂ support, inducing interfacial reorganization and generating additional oxygen defects, thereby enhancing the oxygen storage capacity of the Pt/CeO₂ catalysts. Mobile oxygen species present on the catalyst surface can react with sulfur species adsorbed at active sites, facilitating their oxidation and desorption and contributing to catalytic regeneration. Catalytic evaluations revealed that only transition metal-doped Pt/CeO₂ catalysts maintained enhanced oxygen mobility under sulfur-containing conditions through strong Pt–O–Ce interfacial interactions, resulting in a significant improvement in sulfur tolerance and activity regeneration performance compared with the unpromoted Pt/CeO₂ catalyst. These findings demonstrate that preserving a Pt–O–Ce interfacial structure under sulfur exposure is an additional and previously underappreciated requirement for achieving sulfur tolerance. This insight provides a foundation for the development of highly durable catalyst systems applicable to waste-to-hydrogen technologies.