Pt/CeO2 as Catalyst for Nonoxidative Coupling of Methane: Oxidative Regeneration

Direct nonoxidative coupling is a promising route formethane upgrading,yet its commercialization is hindered by the lack of efficient catalysts.Pt/CeO2 catalysts with isolated Pt species have attractedan increasing amount of interest in recent years. Herein, we studiedthe catalytic role and evolution of isolated Pt centers on CeO2 prepared by flame spray pyrolysis under the harsh reactionconditions of nonoxidative methane coupling. During the reaction at800 & DEG;C, the isolated Pt sites sinter, leading to a loss of theethylene and ethane yield. The agglomerated Pt can be redispersedby using an in situ regeneration strategy in oxygen.We found that isolated Pt centers are able to activate methane onlyat the initial reaction stage, and the CePt5 alloy actsas the active phase in the prolonged reaction.

Automated summary

Direct nonoxidative coupling is a promising route for methane upgrading, but lack of efficient catalysts hinders its commercialization. Recently, Pt/CeO2 catalysts with isolated Pt species have gained increasing attention. In this study, the catalytic role and evolution of isolated Pt centers on CeO2 prepared by flame spray pyrolysis under harsh reaction conditions of nonoxidative methane coupling were investigated. The isolated Pt sites sinter during the reaction at 800°C, resulting in a decrease in ethylene and ethane yield. However, the agglomerated Pt can be redispersed using an in situ regeneration strategy in oxygen. It was found that isolated Pt centers can only activate methane at the initial reaction stage, while the CePt5 alloy acts as the active phase in prolonged reaction.