Highly efficient Ru/CeO2 catalyst using colloidal chemical method for propane oxidation

Abstract

Although supported-Ru catalysts have been widely studied for the light alkane oxidation root in their lower cost compared to Pt and Pd, developing Ru-based catalysts with high efficiency for low-temperature light alkane elimination remains a significant challenge. Herein, Ru/CeO2 catalysts were prepared utilizing the colloidal synthesis (Ru/CeO2-CS) and compared with the catalyst prepared with the traditional impregnation method (Ru/CeO2-IM) in the textural properties and catalytic propane oxidation. It was discovered that Ru/CeO2-CS sample contained a higher concentration of active Ru − O − Ce interface and oxygen vacancies attributed to the strong Ru-CeO2 interaction, which further enhanced the redox capacity. Besides, the lower valence state of Ru species and higher contents of Lewis acid sites on Ru/CeO2-CS sample boosted the adsorption, dissociation, and activation of propane, thus promoting the deep oxidation of propane to CO2 and H2O. The reaction mechanism of propane oxidation was revealed by in-situ DRIFTS, and both the catalysts showed bands related to acrylate species, suggesting that propane underwent an acrylate oxidation pathway on Ru/CeO2-CS and Ru/CeO2-IM samples. The distinct textural properties of these catalysts resulted in Ru/CeO2-CS synthesized by colloidal methods showing a T90 of 170 °C, and Ea of 50.9 ± 1.8 kJ·mol−1, markedly lower than Ru/CeO2-IM prepared with the traditional impregnation method. Apart from the activity, the Ru/CeO2-CS sample obtained superior water resistance, thermal stability, and durability. This comprehensive work provides promising insights into low-temperature propane oxidation.