Issue 18, 2019

Molecular-level understanding of reaction path optimization as a function of shape concerning the metal–support interaction effect of Co/CeO2 on water-gas shift catalysis

Abstract

In this work, the active sites generated in hydrogen reduction and the reaction pathways for the water gas shift (WGS) reaction over Co/CeO2 catalysts were studied by in situ XAS and XPS coupled with DFT+U calculations. In reactions over fresh CeO2 and Co/CeO2 of spindle-, cube-, rod- and sphere-morphology, the CO conversion was less than 30% and did not show much variation across the catalysts. After in situ H2 treatment at 400 °C for 1 h, the Co/CeO2 catalyst of spherical morphology shows an excellent reaction rate and stability. In situ XAS, XPS and H2-TPR results revealed that the H2 treatment results in the strengthening of cobalt–ceria interaction, which is essential for the WGS reaction. It is apparent that the shape of CeO2 has a strong influence on the strength of metal–support interaction which affects the degree of cobalt reduction. According to the results of DFT+U calculations, the WGS reaction follows the associative mechanism on reduced Co/CeO2 catalysts, and the formation of the carboxyl group is found to be the rate-limiting step with an activation barrier of 0.77 eV. Interestingly, the carboxyl intermediate species over pure reduced CeO2(111) are unstable, while these intermediate species can exist stably over the reduced Co/CeO2(111) surface via the strong interaction between Co and Ce, which will promote the WGS performance. The findings of the present study offer new insights into Ce-based catalysts that are suitable for the WGS reaction.

Graphical abstract: Molecular-level understanding of reaction path optimization as a function of shape concerning the metal–support interaction effect of Co/CeO2 on water-gas shift catalysis

Supplementary files

Article information

Article type
Paper
Submitted
24 شوال 1440
Accepted
03 ذو الحجة 1440
First published
04 ذو الحجة 1440

Catal. Sci. Technol., 2019,9, 4928-4937

Molecular-level understanding of reaction path optimization as a function of shape concerning the metal–support interaction effect of Co/CeO2 on water-gas shift catalysis

Y. Zhan, Y. Liu, X. Peng, W. Zhao, Y. Zhang, X. Wang, C. Au and L. Jiang, Catal. Sci. Technol., 2019, 9, 4928 DOI: 10.1039/C9CY01260E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements