English

Active Phase on Oxidized Pd(100) for Low-Temperature Propane Oxidation

• Meijia Xu ,
• Yuchen Zhang ,
• Yifan Zhu ,
• Changlin Li ,
• Zi-Ang Wu ,
• Xiong Zhou ^, ,
• Kai Wu ^,

• College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China

Corresponding author: Email: kaiwu@pku.edu.cn; Tel.: +86-10-62754005 (K.W.); Email: xiongzhou@pku.edu.cn (X.Z.)

• Received Date: 16 May 2023
  Accepted Date: 13 June 2023
  Revised Date: 12 June 2023
  Available Online: 15 October 2023
• Fund Project:

  the National Natural Science Foundation of China 

  the National Natural Science Foundation of China 

  the National Natural Science Foundation of China 

Abstract: Palladium, a key component of three-way catalysts used in automobile exhaust treatment, plays a pivotal role in complete oxidation of alkanes and low-temperature oxidation of CO. Under oxygen-rich conditions, a thin oxide layer spontaneously forms on the palladium surface. To understand the influence of the oxidized palladium surface on the active phase of low-temperature hydrocarbon oxidation, we have conducted a comprehensive study of the oxidation process on Pd(100) and its impact on propane oxidation. Our experimental results reveal that under varying oxidation conditions, the Pd(100) surface sequentially forms three different monolayered oxide phases, namely, (2 × 2)-O, (5 × 5)-PdO and (\begin{document}$ \sqrt{\text{5}} $\end{document} × \begin{document}$ \sqrt{\text{5}} $\end{document}) R27°-PdO. The oxygen coverage correspondingly increases in the order of 0.25 monolayer, 0.56 monolayer and 0.8 monolayer. Notably, (5 × 5)-PdO is identified for the first time by high-resolution scanning tunneling microscopy. Experiments show this structure exhibits typical chiral features with its two enantiomers observed in the experiments. The chiral features of the (5 × 5)-PdO structure may bear significant implications in practical applications like chiral catalysis. Based on high-resolution atomic imaging, we have proposed a new (5 × 5)-PdO structure model. In addition, it's experimentally revealed that upon thermal treatments the (5 × 5)-PdO structure decomposes into the (\begin{document}$ \sqrt{\text{5}} $\end{document} × \begin{document}$ \sqrt{\text{5}} $\end{document}) R27°-PdO and the (2 × 2)-O structures, and the (\begin{document}$ \sqrt{\text{5}} $\end{document} × \begin{document}$ \sqrt{\text{5}} $\end{document}) R27°-PdO decomposes into the (2 × 2)-O structure as well. These results suggest that the thermal stability of these oxide phases is in the order of (2 × 2)-O > (\begin{document}$ \sqrt{\text{5}} $\end{document} × \begin{document}$ \sqrt{\text{5}} $\end{document}) R27°-PdO > (5 × 5)-PdO. We have also compared the catalytic activities of these three oxidation phases in low-temperature propane oxidation. The results show that only the (\begin{document}$ \sqrt{\text{5}} $\end{document} × \begin{document}$ \sqrt{\text{5}} $\end{document}) R27°-PdO could catalyze propane oxidation near room temperature. We have observed a significant number of oxygen defects in the (\begin{document}$ \sqrt{\text{5}} $\end{document} × \begin{document}$ \sqrt{\text{5}} $\end{document}) R27°-PdO, which also forms the reduced (2 × 2)-O phase. Both complete oxidation products H₂O and CO₂ are detectable by temperature-programmed desorption within two main temperature slots around 285 and 315 K. Neither the (2 × 2)-O nor the (5 × 5)-PdO phase shows an obvious catalytic activity. The superior oxidation activity of the (\begin{document}$ \sqrt{\text{5}} $\end{document} × \begin{document}$ \sqrt{\text{5}} $\end{document}) R27°-PdO phase might be associated with its higher O density and hence more active O species within the structure. Our study indicates that the (\begin{document}$ \sqrt{\text{5}} $\end{document} × \begin{document}$ \sqrt{\text{5}} $\end{document}) R27°-PdO serves as the active phase for the low-temperature propane oxidation. These insights would help understand the working mechanisms of three-way catalysts and should be of great importance for the development of efficient and low-temperature three-way catalysts.

Key words:
• Palladium oxide
•  /  Chiral oxide
•  /  Low-temperature propane oxidation
•  /  Scanning tunneling microscopy

• 1. [1]

     李红梅, 兰丽, 陈山虎, 刘达玉, 王卫, 龚茂初, 陈耀强. 物理化学学报, 2016, 32, 1734. doi: 10.3866/PKU.WHXB201603235Li, H. M.; Lan, L.; Chen, S. H.; Liu, D. Y.; Wang, W.; Gong, M. C.; Chen, Y. Q. Acta Phys. -Chim. Sin. 2016, 32, 1734. doi: 10.3866/PKU.WHXB201603235

  2. [2]

     Gao, F.; McClure, S. M.; Cai, Y.; Gath, K. K.; Wang, Y.; Chen, M. S.; Guo, Q. L.; Goodman, D. W. Surf. Sci. 2009, 603, 65. doi: 10.1016/j.susc.2008.10.031

  3. [3]

     贾永昌, 王树元, 孟涟, 鲁继青, 罗孟飞. 物理化学学报, 2016, 32, 1801. doi: 10.3866/PKU.WHXB201604081Jia, Y. C.; Wang, S. Y.; Meng, L.; Lu, J. Q.; Luo, M. F. Acta Phys. -Chim. Sin. 2016, 32, 1801 doi: 10.3866/PKU.WHXB201604081

  4. [4]

     Schwartz, A. J. Catal. 1971, 21, 199. doi: 10.1016/0021-9517(71)90138-2

  5. [5]

     Niu, Y. M.; Liu, X.; Wang, Y. Z.; Zhou, S.; Lv, Z. G.; Zhang, L. Y.; Shi, W.; Li, Y. W.; Zhang, W.; Su, D. S.; et al. Angew. Chem. Int. Ed. 2019, 58, 4232. doi: 10.1002/anie.201812292

  6. [6]

     Zhang, J.; Fan, L.; Zhao, F.; Fu, Y.; Lu, J. Q.; Zhang, Z.; Teng, B.; Huang, W. ChemCatChem 2020, 12, 5540. doi: 10.1002/cctc.202000934

  7. [7]

     Li, R. T.; Xu, X. Y.; Zhu, B. E.; Li, X. Y.; Ning, Y. X.; Mu, R. T.; Du, P. F.; Li, M. W.; Wang, H. K.; Liang, J. J.; et al. Nat. Commun. 2021, 12, 1406. doi: 10.1038/s41467-021-21552-2

  8. [8]

     Hellman, A.; Resta, A.; Martin, N. M.; Gustafson, J.; Trinchero, A.; Carlsson, P. A.; Balmes, O.; Felici, R.; van Rijn, R.; Frenken, J. W. M.; et al. J. Phys. Chem. Lett. 2012, 3, 678. doi: 10.1021/jz300069s

  9. [9]

     Hirvi, J. T.; Kinnunen, T. J. J.; Suvanto, M.; Pakkanen, T. A.; Norskov, J. K. J. Chem. Phys. 2010, 133, 084704. doi: 10.1063/1.3464481

  10. [10]

      Shipilin, M.; Hejral, U.; Lundgren, E.; Merte, L. R.; Zhang, C.; Stierle, A.; Ruett, U.; Gutowski, O.; Skoglundh, M.; Carlsson, P. -A.; et al. Surf. Sci. 2014, 630, 229. doi: 10.1016/j.susc.2014.08.021

  11. [11]

      Hoffmann, M. J.; Reuter, K. Top. Catal. 2014, 57, 159. doi: 10.1007/s11244-013-0172-5

  12. [12]

      Chang, S. L.; Thiel, P. A.; Evans, J. W. Surf. Sci. 1988, 205, 117. doi: 10.1016/0039-6028(88)90167-7

  13. [13]

      Zheng, G.; Altman, E. I. Surf. Sci. 2002, 504, 253. doi: 10.1016/s0039-6028(02)01104-4

  14. [14]

      Mehar, V.; Kim, M.; Shipilin, M.; Van den Bossche, M.; Gustafson, J.; Merte, L. R.; Hejral, U.; Grönbeck, H.; Lundgren, E.; Asthagiri, A.; et al. ACS Catal. 2018, 8, 8553. doi: 10.1021/acscatal.8b02191

  15. [15]

      Rose, M. K.; Borg, A.; Dunphy, J. C.; Mitsui, T.; Ogletree, D. F.; Salmeron, M. Surf. Sci. 2003, 547, 162. doi: 10.1016/j.susc.2003.08.057

  16. [16]

      Orent, T. W.; Bader, S. D. Surf. Sci. 1982, 115, 323. doi: 10.1016/0039-6028(82)90412-5

  17. [17]

      Todorova, M.; Lundgren, E.; Blum, V.; Mikkelsen, A.; Gray, S.; Gustafson, J.; Borg, M.; Rogal, J.; Reuter, K.; Andersen, J. N.; et al. Surf. Sci. 2003, 541, 101. doi: 10.1016/s0039-6028(03)00873-2

  18. [18]

      Kostelník, P.; Seriani, N.; Kresse, G.; Mikkelsen, A.; Lundgren, E.; Blum, V.; Šikola, T.; Varga, P.; Schmid, M. Surf. Sci. 2007, 601, 1574. doi: 10.1016/j.susc.2007.01.026

  19. [19]

      Shipilin, M.; Stierle, A.; Merte, L. R.; Gustafson, J.; Hejral, U.; Martin, N. M.; Zhang, C.; Franz, D.; Kilic, V.; Lundgren, E. Surf. Sci. 2017, 660, 1. doi: 10.1016/j.susc.2017.01.009

  20. [20]

      Huang, Z.; Han, C.; Sun, Y. Y.; Wu, K.; Chen, W. J. Phys. Chem. C 2021, 125, 15599. doi: 10.1021/acs.jpcc.1c03682

  21. [21]

      Huang, Z. C.; Xu, Z.; Zhou, J. Y.; Chen, H. R.; Rong, W. H.; Lin, Y. X.; Wen, X. J.; Zhu, H.; Wu, K. J. Phys. Chem. C 2019, 123, 17823. doi: 10.1021/acs.jpcc.9b03253

  22. [22]

      Zhang, Y.; Feng, W.; Yang, F.; Bao, X. H. Chin. J. Catal. 2019, 40, 204. doi: 10.1016/s1872-2067(18)63171-7

  23. [23]

      赵新飞, 陈浩, 吴昊, 王睿, 崔义, 傅强, 杨帆, 包信和. 物理化学学报, 2018, 34, 1373. doi: 10.3866/PKU.WHXB201804131Zhao, X. F.; Chen, H.; Wu, H.; Wang, R.; Cui, Y.; Fu, Q.; Yang, F.; Bao, X. H. Acta Phys. -Chim. Sin. 2018, 34, 1373. doi: 10.3866/PKU.WHXB201804131

  24. [24]

      Hendriksen, B. L. M.; Bobaru, S. C.; Frenken, J. W. M. Surf. Sci. 2004, 552, 229. doi: 10.1016/j.susc.2004.01.025

  25. [25]

      Zheng, G.; Altman, E. I. J. Phys. Chem. B 2002, 106, 1048. doi: 10.1021/jp013395x

  26. [26]

      van Rijn, R.; Balmes, O.; Resta, A.; Wermeille, D.; Westerstrom, R.; Gustafson, J.; Felici, R.; Lundgren, E.; Frenken, J. W. Phys. Chem. Chem. Phys. 2011, 13, 13167. doi: 10.1039/c1cp20989b

  27. [27]

      Toyoshima, R.; Yoshida, M.; Monya, Y.; Suzuki, K.; Mun, B. S.; Amemiya, K.; Mase, K.; Kondoh, H. J. Phys. Chem. Lett. 2012, 3, 3182. doi: 10.1021/jz301404n

  28. [28]

      Weaver, J. F.; Hakanoglu, C.; Hawkins, J. M.; Asthagiri, A. J. Chem. Phys. 2010, 132, 024709. doi: 10.1063/1.3277672

  29. [29]

      Weaver, J. F.; Devarajan, S. P.; Akanoglu, C. J. Phys. Chem. C 2009, 113, 9773. doi: 10.1021/jp9013114

  30. [30]

      Antony, A.; Asthagiri, A.; Weaver, J. F. Phys. Chem. Chem. Phys. 2012, 14, 12202. doi: 10.1039/c2cp41900a

  31. [31]

      Wrobel, R. J.; Becker, S. Vacuum 2010, 84, 1258. doi: 10.1016/j.vacuum.2010.01.056

  32. [32]

      Huang, W. X.; Zhai, R. S.; Bao, X. H. Surf. Sci. 1999, 439, L803. doi: 10.1016/s0039-6028(99)00820-1

  33. [33]

      Rose, M. K.; Borg, A.; Mitsui, T.; Ogletree, D. F.; Salmeron, M. J. Chem. Phys. 2001, 115, 10927. doi: 10.1063/1.1420732

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