Issue 9, 2022, Issue in Progress

Praseodymia–titania mixed oxide supported gold as efficient water gas shift catalyst: modulated by the mixing ratio of oxides

Abstract

Modulating the active sites for controllable tuning of the catalytic activity has been the goal of much research, however, this remains challenging. The O vacancy is well known as an active site in reducible oxides. To modify the activity of O vacancies in praseodymia, we synthesized a series of praseodymia–titania mixed oxides. Varying the Pr : Ti mole ratio (2 : 1, 1 : 2, 1 : 1, 1 : 4) allows us to control the electronic interactions between Au, Pr and Ti cations and the local chemical environment of the O vacancies. These effects have been studied study by X-ray photoelectron spectroscopy (XPS), CO diffuse reflectance Fourier transform infrared spectroscopy (CO-DRIFTS) and temperature-programmed reduction (CO-TPR, H2-TPR). The water gas shift reaction (WGSR) was used as a benchmark reaction to test the catalytic performance of different praseodymia–titania supported Au. Among them, Au/Pr1Ti2Ox was identified to exhibit the highest activity, with a CO conversion of 75% at 300 °C, which is about 3.7 times that of Au/TiO2 and Au/PrOx. The Au/Pr1Ti2Ox also exhibited excellent stability, with the conversion after 40 h time-on-stream at 300 °C still being 67%. An optimal ratio of Pr content (Pr : Ti 1 : 2) is necessary for improving the surface oxygen mobility and oxygen exchange capability, a higher Pr content leads to more O vacancies, however with lower activity. This study presents a new route for modulating the active defect sites in mixed oxides which could also be extended to other heterogeneous catalysis systems.

Graphical abstract: Praseodymia–titania mixed oxide supported gold as efficient water gas shift catalyst: modulated by the mixing ratio of oxides

Supplementary files

Article information

Article type
Paper
Submitted
23 Nov 2021
Accepted
01 Feb 2022
First published
14 Feb 2022
This article is Open Access
Creative Commons BY-NC license

RSC Adv., 2022,12, 5374-5385

Praseodymia–titania mixed oxide supported gold as efficient water gas shift catalyst: modulated by the mixing ratio of oxides

W. Zhao, J. Shi, M. Lin, L. Sun, H. Su, X. Sun, T. Murayama and C. Qi, RSC Adv., 2022, 12, 5374 DOI: 10.1039/D1RA08572G

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