On the nature of the deactivation of supported palladium nanoparticle catalysts in the decarboxylation of fatty acids.

Journal Article · Fri Apr 15 00:00:00 EDT 2011 · Applied Catalysis. A, General

DOI:https://doi.org/10.1016/j.apcata.2011.01.042· OSTI ID:1029104

Ping, E W; Pierson, J; Wallace, R; Miller, J T; Fuller, T F; Jones, C W ^[1]

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1. Chemical Sciences and Engineering Division

Supported palladium catalysts are effective catalysts for the hydrogen-free decarboxylation of fatty acids. However, the catalysts deactivate severely after one use. Here, the recyclability of a well-defined, mesoporous silica-supported palladium nanoparticle catalyst is evaluated in the batch decarboxylation of stearic acid at 300 C under inert atmosphere, producing n-heptadecane. The nature of the catalyst deactivation is examined in detail via an array of characterization techniques. X-ray photoelectron spectroscopy (XPS) demonstrates that little palladium surface oxidation occurs over the course of the reaction, and a combination of X-ray absorption spectroscopy and transmission electron microscopy (TEM) suggests negligible particle sintering or agglomeration. Physisorption and chemisorption measurements demonstrate substantial loss in total surface area and porosity as well as accessible palladium surface area with these losses attributed to significant organic deposition on the catalyst, as verified via thermogravimetric analysis. High temperature calcination is applied to combust and remove these residues, but resultant nanoparticle agglomeration is significant. Solid state nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FT-IR) and solid dissolution followed by organic extraction methodologies demonstrate that the carbonaceous deposits are not coke but rather strongly adsorbed reactants and products. Detrimental coke formation, as suggested by prior literature, is verified to be absent, as extraction of the surface-deposited organic species yields nearly complete recovery of the total surface area, pore volume, and active palladium surface area. Furthermore, the regenerated catalyst exhibits a corresponding significant recovery of decarboxylation activity.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC); The State of Georgia Food Industry Partnership; Georgia Tech Research Institute Agricultural Technology Research Program
• DOE Contract Number: DE-AC02-06CH11357
• OSTI ID: 1029104
• Report Number(s): ANL/CSE/JA-71424; ACAGE4; TRN: US201123%%9
• Journal Information: Applied Catalysis. A, General, Vol. 396, Issue 1-2; ISSN 0926-860X
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

60 APPLIED LIFE SCIENCES
ABSORPTION SPECTROSCOPY
AGGLOMERATION
CALCINATION
CARBOXYLIC ACIDS
CATALYSTS
CHEMISORPTION
DEACTIVATION
DECARBOXYLATION
INERT ATMOSPHERE
NUCLEAR MAGNETIC RESONANCE
OCTADECANOIC ACID
OXIDATION
PALLADIUM
POROSITY
RESIDUES
SINTERING
SPECTROSCOPY
SURFACE AREA
THERMAL GRAVIMETRIC ANALYSIS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY PHOTOELECTRON SPECTROSCOPY