A mechanic insight into low-temperature catalytic combustion toward ethylene oxide over Pt-Ru/CuCeOx bimetallic catalyst

The catalytic oxidation performance toward ethylene oxide (EO) and the consequent mechanism were investigated on the Pt-Ru/CuCeOx bimetallic catalyst, which was prepared by a distinct method combining stepwise adsorption and subsequent impregnation. The catalytic tests show that the introduction of Ru into the Pt catalyst, so as to form Pt-Ru bimetallic active sites, can greatly increase the oxidation activity of the catalyst, as evidenced by the extremely lower full oxidation temperature (120 degrees C) when compared with that of the Pt/CeO2 catalyst (160 degrees C). The XPS spectra show that the Ru species (mainly RuOx) have strong interaction with the CuCeOx support, which can therefore affect the electron transfer between the Pt species and the support. As a result, the oxygen activation on Pt species is obviously facilitated and catalytic activity is enhanced. Finally, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) was used to track the reaction mechanism. It is found that the catalytic oxidation process follows the MvK catalytic mechanism at low temperature and the L-H catalytic mechanism when the temperature moves to higher range.(c) 2023 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.

Automated summary

In this study, the catalytic performance and mechanism of ethylene oxide oxidation on Pt-Ru/CuCeOx bimetallic catalyst were investigated. The results showed that the introduction of Ru into the Pt catalyst greatly enhanced the oxidation activity, with a lower full oxidation temperature compared to Pt/CeO2 catalyst. XPS spectra revealed strong interaction between Ru species and the CuCeOx support, which facilitated oxygen activation on Pt species and enhanced catalytic activity. DRIFTs analysis indicated that the oxidation process followed the MvK catalytic mechanism at low temperature and the L-H catalytic mechanism at higher temperature.