The Effect of SO 2 and H 2 O on the Interaction Between Pt and TiO 2 (P-25) During Catalytic CO Oxidation
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The Effect of SO2 and H2O on the Interaction Between Pt and TiO2(P-25) During Catalytic CO Oxidation Kenji Taira1,2 · Hisahiro Einaga1 Received: 8 October 2018 / Accepted: 11 January 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019
Abstract The deactivation of noble metal catalysts by S O2 and H 2O is a common issue in the post combustion treatment of flue gases from sintering processes in the steel industry. In an effort to develop SO2-tolerant CO-oxidation catalysts, herein, we investigated the effect of S O2 and H 2O on the catalytic activity of Pt/TiO2(P-25) catalysts for CO oxidation using X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and diffuse-reflectance infrared Fourier-transform O2 and presence of H 2O, enhanced the activity and (DRIFT) spectroscopy. Pt/TiO2(P-25) catalysts, in the absence of S stability of CO oxidation, while being largely suppressed and irreversibly deactivated in the presences of SO2. The XPS and TEM results suggested that variations in the Pt particle size and oxidation state were not major causes of the deactivation. Instead, according to DRIFT spectra, the interaction between CO and H2O at the metal-support interface was weakened after the formation of T iOSO4 on the T iO2 surface in the presence of S O2. This resulted in a loss of the previously observed enhancement of CO oxidation under humid conditions. These results indicate that in the presence of S O2, the formation of TiOSO4 is the major cause of irreversible deactivation. Therefore, removal of the TiOSO4 layer from the T iO2 surface is a crucial step for catalyst regeneration. Graphical Abstract Pristine Pt/TiO2
Exposed to H2O & SO2
CO2 CO2 CO2 Pt
CO+O2 Interaction
CO2
TiO2
CO+O2
Pt TiOSO4 TiO2
No Interaction
Keywords Catalyst regeneration · CO oxidation · Platinum catalyst · SO2 · TiO2
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10562-019-02672-3) contains supplementary material, which is available to authorized users. * Kenji Taira [email protected] 1
Department of Material Sciences, Faculty of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816‑8580, Japan
Advanced Technology Research Laboratories, Nippon Steel & Sumitomo Metal Corporation, 20‑1 Shintomi, Futtsu, Chiba 293‑8511, Japan
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1 Introduction TiO2 is frequently used as a supporting material for metal and metal oxide catalysts due to its high surface area, strong metal-support interactions, and chemical stability [1]. These properties also make T iO2-supported metal or metal oxide catalysts promising for applications such as those related to the production of fine chemicals and catalytic CO oxidation. Among supporting materials for noble metal catalysts, TiO2-supported Pt (Pt/TiO2) catalysts showed higher activity for CO oxidation than other supported Pt catalysts (e.g., Pt/
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SiO2) due to the interaction between Pt and the TiO2 support [2]. One useful
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