Catalytic Oxidation of Propane over Palladium Alloyed with Gold: An Assessment of the Chemical and Intermediate Species

Journal Article · 13 November 2018 · Catalysis Science and Technology

DOI: https://doi.org/10.1039/c8cy01704b · OSTI ID:1610909

Kareem, Haval ^[1]; Shan, Shiyao ^[2]; Wu, Zhi-Peng ^[2]; Velasco, Leslie ^[2]; Moseman, Kelli ^[2]; O'Brien, Casey P. ^[3]; Tran, Dat T. ^[3]; Lee, Ivan C. ^[3]; Maswadeh, Yazan ^[4]; Yang, Lefu ^[5]; Mott, Derrick ^[6]; Luo, Jin ^[2]; Petkov, Valeri  ^[4]; Zhong, Chuan-Jian  ^[2]

---

1. State Univ. of New York (SUNY), Binghamton, NY (United States); DOE/OSTI
2. State Univ. of New York (SUNY), Binghamton, NY (United States)
3. Army Research Lab., Adelphi, MD (United States)
4. Central Michigan Univ., Mount Pleasant, MI (United States)
5. Xiamen Univ. (China)
6. Japan Advanced Institute of Science and Technology, Nomi, Ishikawa (Japan)

Understanding the catalytic oxidation of propane is important for developing catalysts not only for catalytic oxidation of hydrocarbons in emission systems but also for selective oxidation in the chemical processing industry. For palladium-based catalysts, little is known about the identification of the chemical or intermediate species involved in propane oxidation. We describe herein findings of an investigation of the catalytic oxidation of propane over supported palladium nanoalloys with different compositions of gold (Pd_nAu_100–n), focusing on probing the chemical or intermediate species on the catalysts in correlation with the bimetallic composition and the alloying phase structure. In addition to an enhanced catalytic activity, a strong dependence of the catalytic activity on the bimetallic composition was revealed, displaying an activity maximum at a Pd : Au ratio of 50 : 50 in terms of reaction temperature. This dependence is also reflected by its dependence on the thermochemical treatment conditions. While the activity for nanoalloys with n ~ 50 showed little change after the thermochemical treatment under oxygen, the activities for nanoalloys with n < 50 and n > 50 showed opposite trends. Importantly, this catalytic synergy is linked to the subtle differences of chemical and intermediate species which have been identified for the catalysts with different bimetallic compositions by in situ measurements using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). For the catalytic oxidation of propane over the highly-active catalyst with a Pd : Au ratio of 50 : 50, the major species identified include acetate and bicarbonate, showing subtle differences in comparison with the identification of bicarbonate and formate for the catalyst with <50% Au (with a lower activity) and the absence of apparent species for the catalyst with >50% Au (activity is largely absent). The alloying of 50% Au in Pd is believed to increase the oxophilicity of Pd, which facilitates the first carbon–carbon bond cleavage and oxygenation of propane. Finally, the implications of the findings on the catalytic synergy of Pd alloyed with Au and the design of active Pd alloy catalysts are also discussed.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Central Michigan Univ., Mount Pleasant, MI (United States)
• Sponsoring Organization: National Science Foundation (NSF); US Department of Education; USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357; SC0006877
• OSTI ID: 1610909
• Journal Information: Catalysis Science and Technology, Journal Name: Catalysis Science and Technology Journal Issue: 23 Vol. 8; ISSN CSTAGD; ISSN 2044-4753
• Publisher: Royal Society of ChemistryCopyright Statement
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
chemistry
in-situ DRIFTS probing
intermediate species
palladium-gold nanoparticles
propane oxidation
support effect
surface catalytic sites
thermochemically-tuned nanoalloys