TY - JOUR
T1 - Promoting effect of basic metal additives on DeNOx reactions over Pt-based three-way catalysts
AU - Jing, Yuan
AU - Wang, Gang
AU - Mine, Shinya
AU - Kawai, Jumpei
AU - Toyoshima, Ryo
AU - Kondoh, Hiroshi
AU - Zhang, Xiaorui
AU - Nagaoka, Shuhei
AU - Shimizu, Ken ichi
AU - Toyao, Takashi
N1 - Funding Information:
This study was financially supported by KAKENHI (Grant Nos. 20H02775, 20KK0111, 20F20345, 21K18185, 22K14538, and 22J11835) from JSPS, the JST-CREST project JPMJCR17J3, and the Joint Usage/Research Center for Catalysis. G.W. and Y.J. acknowledge the JSPS postdoctoral fellowship (P20345). The authors would like to thank the technical staff at the Open Facility of Hokkaido University for their assistance with the STEM experiments. XAS measurements were conducted at the BL-14B2 beamline of SPring-8 (2020A1695 and 2021B1840). AP-XPS experiments were performed with the approval of the Photon Factory Program Advisory Committee (PF PAC No. 2021G009).
Funding Information:
This study was financially supported by KAKENHI (Grant Nos. 20H02775, 20KK0111, 20F20345, 21K18185, 22K14538, and 22J11835) from JSPS, the JST-CREST project JPMJCR17J3, and the Joint Usage/Research Center for Catalysis. G.W. and Y.J. acknowledge the JSPS postdoctoral fellowship (P20345). The authors would like to thank the technical staff at the Open Facility of Hokkaido University for their assistance with the STEM experiments. XAS measurements were conducted at the BL-14B2 beamline of SPring-8 (2020A1695 and 2021B1840). AP-XPS experiments were performed with the approval of the Photon Factory Program Advisory Committee (PF PAC No. 2021G009).
Publisher Copyright:
© 2022 Elsevier Inc.
PY - 2022/12
Y1 - 2022/12
N2 - Pt has been economically favored over Rh and Pd. However, Pt-based three-way catalysts (TWCs) have been studied less than Pd- and Rh-based TWCs; therefore, their properties have not yet been sufficiently evaluated, especially under conditions relevant to modern three-way catalysis operation, wherein deviations from stoichiometric conditions are often encountered. In this study, we examined the promotional effect of basic metal additives in Pt/M/Al2O3 (M = Ba, La, Sr) on the efficiency of three-way catalytic reactions. The catalytic activities of the Pt/M/Al2O3 catalysts for NO, CO, and total hydrocarbons were superior to those of Pt/Al2O3; moreover, Ba enhanced the catalytic activity of Pt-based catalysts more efficiently than La and Sr. The best-performing catalyst, Pt/Ba/Al2O3, was subjected to kinetic studies and various in situ/operando spectroscopic experiments, namely, X-ray absorption spectroscopy, infrared spectroscopy, and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS), to investigate the role of Ba in the NO reduction reaction. The Pt0 species loaded on Ba/Al2O3 were more electron-rich than those loaded on Al2O3, thereby promoting NO dissociation into N and O atoms, as revealed by the AP-XPS results. Moreover, the efficient formation of intermediate surface NOx species, including nitrites and nitrates, and their reactivities toward reductant gases, such as H2 or CO, were critical for promoting the effect of Ba on the NO reduction reaction.
AB - Pt has been economically favored over Rh and Pd. However, Pt-based three-way catalysts (TWCs) have been studied less than Pd- and Rh-based TWCs; therefore, their properties have not yet been sufficiently evaluated, especially under conditions relevant to modern three-way catalysis operation, wherein deviations from stoichiometric conditions are often encountered. In this study, we examined the promotional effect of basic metal additives in Pt/M/Al2O3 (M = Ba, La, Sr) on the efficiency of three-way catalytic reactions. The catalytic activities of the Pt/M/Al2O3 catalysts for NO, CO, and total hydrocarbons were superior to those of Pt/Al2O3; moreover, Ba enhanced the catalytic activity of Pt-based catalysts more efficiently than La and Sr. The best-performing catalyst, Pt/Ba/Al2O3, was subjected to kinetic studies and various in situ/operando spectroscopic experiments, namely, X-ray absorption spectroscopy, infrared spectroscopy, and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS), to investigate the role of Ba in the NO reduction reaction. The Pt0 species loaded on Ba/Al2O3 were more electron-rich than those loaded on Al2O3, thereby promoting NO dissociation into N and O atoms, as revealed by the AP-XPS results. Moreover, the efficient formation of intermediate surface NOx species, including nitrites and nitrates, and their reactivities toward reductant gases, such as H2 or CO, were critical for promoting the effect of Ba on the NO reduction reaction.
KW - AP-XPS
KW - In situ/operando spectroscopy
KW - Pt/M/AlO
KW - Three-way catalysis
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U2 - 10.1016/j.jcat.2022.10.018
DO - 10.1016/j.jcat.2022.10.018
M3 - Article
AN - SCOPUS:85141806822
SN - 0021-9517
VL - 416
SP - 209
EP - 221
JO - Journal of Catalysis
JF - Journal of Catalysis
ER -