Promotional effect of lanthana on the high-temperature thermal stability of Pt/TiO2 sulfur-resistant diesel oxidation catalysts

Zhengzheng Yang; Na Zhang; Yi Cao; Yunxiang Li; Yunwen Liao; Youping Li; Maochu Gong; Yaoqiang Chen

doi:10.1039/C7RA00582B

Promotional effect of lanthana on the high-temperature thermal stability of Pt/TiO₂ sulfur-resistant diesel oxidation catalysts†

Zhengzheng Yang,

*^a Na Zhang,^a Yi Cao,^b Yunxiang Li,^a Yunwen Liao,^a Youping Li,^a Maochu Gong^bc and Yaoqiang Chen*^bc

Author affiliations

* Corresponding authors

^a College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, Sichuan, China
E-mail: zyang@cwnu.edu.cn
Fax: +86 817 2568646
Tel: +86 817 2568646

^b Key Laboratory of Green Chemistry & Technology of the Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, Sichuan, China
E-mail: nic7501@scu.edu.cn
Fax: +86 28 85418451
Tel: +86 28 85418451

^c Sichuan Provincial Vehicular Exhaust Gases Abatement Engineering Technology Center, Chengdu 610064, Sichuan, China

Abstract

In order to efficiently remove diesel exhaust pollutants during long-term application under high temperature conditions, enhancing the thermal stability of catalysts is essential. Here, lanthana was introduced into a TiO₂ sulfur-resistant support via co-precipitation, and then a Pt/TiO₂–La₂O₃ diesel oxidation catalyst (DOC) was prepared using the impregnation method. The SO₂ uptake and EDX results indicate that the La₂O₃-doped Pt/TiO₂–La₂O₃ catalyst displays superior sulfur resistance compared to the commercial Pt/Al₂O₃ and Pt–Pd/CeO₂–ZrO₂–Al₂O₃ DOC catalysts. Catalytic performance measurements showed that the as-prepared Pt/TiO₂–La₂O₃ catalyst exhibited significantly better activity than Pt/TiO₂ after high-temperature thermal aging and simulative 160 000 km vehicle aging. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and N₂ adsorption–desorption results suggest that some of the La³⁺ dopant ions migrated to the grain boundary of the TiO₂ crystal and other La³⁺ ions replaced Ti⁴⁺ ionic sites to form Ti–O–La bands, which impeded the crystal growth and phase transition of TiO₂, and hence mitigated the destruction of the porous texture of TiO₂. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) observations further demonstrate that the introduction of lanthana into TiO₂ suppressed Pt particle agglomeration and catalyst particle sintering, consequently enhancing the thermal stability of the Pt/TiO₂–La₂O₃ catalyst. Thus, this work shows that lanthana can play an extremely important role in improving the structural and textural stability of TiO₂ and stabilizing the surface-active component of the Pt/TiO₂ DOC catalyst, hence enhancing the high-temperature aging resistance.

Supplementary files

Article information

DOI: https://doi.org/10.1039/C7RA00582B
Article type: Paper
Submitted: 14 Jan 2017
Accepted: 23 Mar 2017
First published: 31 Mar 2017
This article is Open Access

Download Citation

RSC Adv., 2017,7, 19318-19329

Permissions

Request permissions

Promotional effect of lanthana on the high-temperature thermal stability of Pt/TiO₂ sulfur-resistant diesel oxidation catalysts

Z. Yang, N. Zhang, Y. Cao, Y. Li, Y. Liao, Y. Li, M. Gong and Y. Chen, RSC Adv., 2017, 7, 19318 DOI: 10.1039/C7RA00582B

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, 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 commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

RSC Advances