Insights into the Role of Pt Promoter in Co/TiO 2 Catalysts for CO Hydrogenation

Abstract

Platinum is widely used as a reduction promoter in transition metal heterogeneous catalysts, while its effects on the catalyst’s properties and CO hydrogenation behavior remain unclear. In this study, an improvement in the reducibility of platinum-promoted catalysts is observed. Notably, platinum suppresses the aggregation of cobalt nanoparticles (CoNPs) during catalyst preparation, as evidenced by STEM/TEM and XRD analyses, which reveal the presence of smaller CoNPs and weakened cobalt diffraction in platinum-promoted catalysts. In addition, platinum also promotes the formation of more active hexagonal close-packed (hcp) cobalt but inhibits metal-support interaction (MSI). Therefore, the cobalt-time yield (CTY) for CO hydrogenation in the promoted catalyst is strongly improved, and, furthermore, its intrinsic activity (turnover frequency, TOF) is also slightly increased. However, the product distribution seems unchanged except for the CO2 for the platinum-promoted catalysts.