Title: Effects of water on the kinetics of acetone hydrogenation over Pt and Ru catalysts

Abstract

We employed an approach combining reaction kinetics measurements at steady state conditions, electronic structure calculations employing density functional theory, and microkinetic modeling for acetone hydrogenation to provide insights into the effects of water on metal catalyst surfaces for the hydrogenation of oxygenates over a wide range of reaction conditions. Elucidation of the repulsive interactions due to adsorbed water molecules at various reaction conditions provides a basis to formulate rate expressions for heterogeneous catalytic processes of biomass oxygenates. Reaction kinetics experiments were carried out at partial pressures of H₂, acetone, water and helium in the range of 0.51-0.79, 0.02-0.13, 0.08-0.23, 0-0.28 atm, respectively. We show that the addition of water enhances the hydrogenation rate at 353 K and 1 atm on oxophilic metal catalysts such as Ru/C, whereas the same promotional effect of water is not observed for Pt-based catalysts. Microkinetic model predictions for the hydrogenation of acetone on Ru in the absence and presence of water, using enthalpies and entropies obtained from DFT calculations, were in agreement with the experimentally observed reaction orders and activation barriers. The model shows that a water-assisted hydroxypropyl path is expected to be the favored path on Ru with a rate-determining step of H-OH-mediated hydrogenationmore » of C₃H₆OH (i.e., the hydroxypropyl intermediate formed by H₂O-mediated initial hydrogenation of acetone) to produce isopropyl alcohol (IPA). Furthermore, hydrogen, acetone, hydroxypropyl intermediate and hydroxyl species were predicted to be abundant on the Ru surface with a high coverage of nearly 85%. Lastly, the combined studies of computational and experimental catalysis on hydrogenation reactions help to elucidate the mechanistic role of water on metal catalyzed reactions for producing chemical building blocks from biomass-derived oxygenates.« less

Authors:

Demir, Benginur  ^[1];

• Search DOE PAGES for author "Demir, Benginur"
• Search DOE PAGES for ORCID "0000-0003-3469-906X"

Kropp, Thomas  ^[1];

• Search DOE PAGES for author "Kropp, Thomas"
• Search DOE PAGES for ORCID "0000-0002-9166-566X"

Gilcher, Elise B. ^[1]; Mavrikakis, Manos  ^[1];

• Search DOE PAGES for author "Mavrikakis, Manos"
• Search DOE PAGES for ORCID "0000-0002-5293-5356"

Dumesic, James A.  ^[1]

• Search DOE PAGES for author "Dumesic, James A."
• Search DOE PAGES for ORCID "0000-0001-6542-0856"

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+ Show Author Affiliations

1. Univ. of Wisconsin, Madison, WI (United States)

Publication Date:

Thu Mar 18 00:00:00 EDT 2021

Research Org.:

Univ. of Wisconsin, Madison, WI (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; USDOE

OSTI Identifier:

1778261

Alternate Identifier(s):

OSTI ID: 1836138

Grant/Contract Number:  

SC0014058; FG02-05ER15731; AC02-05CH11231; AC02-06CH11357

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Catalysis

Additional Journal Information:

Journal Volume: 403; Journal ID: ISSN 0021-9517

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; platinum; ruthenium; acetone; hydrogenation; density functional theory; microkinetic model; reaction kinetics