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ORIGINAL RESEARCH

DFT calculations and in situ DRIFTS study of CO oxidation on CeO2/Co3O4 catalyst Liping Ye 1,2,3 & Bingxing Yang 1,2,3 & Yong Luo 1,2,3,4 Received: 24 August 2020 / Accepted: 5 October 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020

Abstract The surface structures, CO adsorption, and oxidation-reaction properties of CeO2/Co3O4(110) have been investigated by using density functional theory including on-site Coulomb corrections (DFT+U) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). Results indicate that CO can be chemisorbed on the Co sites of the terrace and interface of CeO2/Co3O4(110). At the interface, adsorbed and gas-phase CO reacting with lattice oxygen are investigated, respectively. It has been found that the lattice oxygen at the interface is more likely to be attacked by gas-phase CO directly to form adsorbed CO2. For desorption of the CO2, very high energy barriers are required. Furthermore, the infrared spectra reveal that the intermediate species at interface still exist even at 300 °C. Keywords DFT . CO oxidation . Copper-ceria interaction . Interface

Introduction Catalysts for CO catalytic oxidation have important application value in olefin raw material purification [1], gas sensor [2], fuel cells [3], etc. Co3O4 has been widely concerned because of its excellent catalytic activity for CO oxidation at low temperature [4–6]. It is considered as one of the most potential materials to replace noble metal catalysts. The CoO bond energy of Co3O4 surface is weak, which can provide active lattice oxygen for CO oxidation reaction [7]. Wang et al. [8] studied the CO oxidation reaction on different metal oxide surfaces by DFT calculation. The results showed that the adsorption of CO on the surface of Co3O4

* Bingxing Yang [email protected] 1

State Key Laboratory of Polyolefins and Catalysis, Shanghai 200062, People’s Republic of China

2

Shanghai Key Laboratory of Catalysis Technology for Polyolefins, Shanghai 200062, People’s Republic of China

3

Shanghai Research Institute of Chemical Industry CO., LTD, Shanghai 200062, People’s Republic of China

4

Shanghai Institute of Technology, Shanghai 201418, People’s Republic of China

was stronger and the reaction energy barrier was lower than that of other oxides. Compared with single-component structures, multicomponent hybrid structures usually exhibit enhanced catalytic performance as they have some additional effects such as synergistic effect and interfacial effect. It is well known that CeO2 contains Ce3+/Ce4+ redox pairs and is usually used as an accelerator in catalysts. The composite oxides formed by the combination of Co3O4 and CeO2 show high CO catalytic activity [9–11]. For instance, Tang et al. [12, 13] studied the modification of CeO2 on high surface area Co3O4 as well as the promotion effect of CO oxidation via different pretreatment conditions, and showed that CeO2/Co3O4 catalyst had excellent catalytic performance for CO oxidation at low temperatur