Impact of alkali acetate promoters on the dynamic ordering of PdAu catalysts during vinyl acetate synthesis

Elisabeth K. Hanrieder; Andreas Jentys; Johannes A. Lercher

doi:10.1016/j.jcat.2015.10.019

Impact of alkali acetate promoters on the dynamic ordering of PdAu catalysts during vinyl acetate synthesis

Elisabeth K. Hanrieder
, Andreas Jentys
, Johannes A. Lercher

Technical University of Munich

Research output: Contribution to journal › Article › peer-review

22 Scopus citations

Abstract

Fresh and used alkali acetate (MOAc with M⁺ = Li⁺, Na⁺, K⁺, Cs⁺) promoted bimetallic PdAu catalysts were studied to investigate the impact of the alkali metal cations on the deactivation of the catalysts during vinyl acetate (VA) synthesis from ethene and acetic acid. Dynamic reordering of PdAu toward an active Pd₁Au₁ phase, a less active M₂Pd₂(OAc)₆ and inactive Pd₃(OAc)₆ complexes determines the overall activity. Decreasing deactivation from LiOAc to CsOAc promoted PdAu can be associated with the lower concentration of inactive Pd₃(OAc)₆ leached from the active PdAu particles and with the lower loss of Cs⁺ compared to Li⁺ during reaction. CsOAc binds most efficiently to Pd₃(OAc)₆ and forms active Cs₂Pd₂(OAc)₆, lowering the tendency to leach Cs⁺. Reduction of Pd in M₂Pd₂(OAc)₆ to a mixed "Pd/M⁺-O" adlayer on the bimetallic PdAu particles stabilized active Pd⁰ on the PdAu surface maintaining the catalyst activity. Thus, increasing "Pd/M⁺-O" concentrations from LiOAc to CsOAc lower long-term deactivation of PdAu.

Original language	English
Pages (from-to)	71-77
Number of pages	7
Journal	Journal of Catalysis
Volume	333
DOIs	https://doi.org/10.1016/j.jcat.2015.10.019
State	Published - Jan 2016

Keywords

Absorption/extinction coefficient
CO adsorption
Dynamic reordering of silica supported Pd-Au alloy particles
EXAFS
In situ IR spectroscopy

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10.1016/j.jcat.2015.10.019

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title = "Impact of alkali acetate promoters on the dynamic ordering of PdAu catalysts during vinyl acetate synthesis",

abstract = "Fresh and used alkali acetate (MOAc with M+ = Li+, Na+, K+, Cs+) promoted bimetallic PdAu catalysts were studied to investigate the impact of the alkali metal cations on the deactivation of the catalysts during vinyl acetate (VA) synthesis from ethene and acetic acid. Dynamic reordering of PdAu toward an active Pd1Au1 phase, a less active M2Pd2(OAc)6 and inactive Pd3(OAc)6 complexes determines the overall activity. Decreasing deactivation from LiOAc to CsOAc promoted PdAu can be associated with the lower concentration of inactive Pd3(OAc)6 leached from the active PdAu particles and with the lower loss of Cs+ compared to Li+ during reaction. CsOAc binds most efficiently to Pd3(OAc)6 and forms active Cs2Pd2(OAc)6, lowering the tendency to leach Cs+. Reduction of Pd in M2Pd2(OAc)6 to a mixed {"}Pd/M+-O{"} adlayer on the bimetallic PdAu particles stabilized active Pd0 on the PdAu surface maintaining the catalyst activity. Thus, increasing {"}Pd/M+-O{"} concentrations from LiOAc to CsOAc lower long-term deactivation of PdAu.",

keywords = "Absorption/extinction coefficient, CO adsorption, Dynamic reordering of silica supported Pd-Au alloy particles, EXAFS, In situ IR spectroscopy",

author = "Hanrieder, \{Elisabeth K.\} and Andreas Jentys and Lercher, \{Johannes A.\}",

note = "Publisher Copyright: {\textcopyright} 2015 Elsevier Inc.",

year = "2016",

month = jan,

doi = "10.1016/j.jcat.2015.10.019",

language = "English",

volume = "333",

pages = "71--77",

journal = "Journal of Catalysis",

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TY - JOUR

T1 - Impact of alkali acetate promoters on the dynamic ordering of PdAu catalysts during vinyl acetate synthesis

AU - Hanrieder, Elisabeth K.

AU - Jentys, Andreas

AU - Lercher, Johannes A.

PY - 2016/1

Y1 - 2016/1

N2 - Fresh and used alkali acetate (MOAc with M+ = Li+, Na+, K+, Cs+) promoted bimetallic PdAu catalysts were studied to investigate the impact of the alkali metal cations on the deactivation of the catalysts during vinyl acetate (VA) synthesis from ethene and acetic acid. Dynamic reordering of PdAu toward an active Pd1Au1 phase, a less active M2Pd2(OAc)6 and inactive Pd3(OAc)6 complexes determines the overall activity. Decreasing deactivation from LiOAc to CsOAc promoted PdAu can be associated with the lower concentration of inactive Pd3(OAc)6 leached from the active PdAu particles and with the lower loss of Cs+ compared to Li+ during reaction. CsOAc binds most efficiently to Pd3(OAc)6 and forms active Cs2Pd2(OAc)6, lowering the tendency to leach Cs+. Reduction of Pd in M2Pd2(OAc)6 to a mixed "Pd/M+-O" adlayer on the bimetallic PdAu particles stabilized active Pd0 on the PdAu surface maintaining the catalyst activity. Thus, increasing "Pd/M+-O" concentrations from LiOAc to CsOAc lower long-term deactivation of PdAu.

AB - Fresh and used alkali acetate (MOAc with M+ = Li+, Na+, K+, Cs+) promoted bimetallic PdAu catalysts were studied to investigate the impact of the alkali metal cations on the deactivation of the catalysts during vinyl acetate (VA) synthesis from ethene and acetic acid. Dynamic reordering of PdAu toward an active Pd1Au1 phase, a less active M2Pd2(OAc)6 and inactive Pd3(OAc)6 complexes determines the overall activity. Decreasing deactivation from LiOAc to CsOAc promoted PdAu can be associated with the lower concentration of inactive Pd3(OAc)6 leached from the active PdAu particles and with the lower loss of Cs+ compared to Li+ during reaction. CsOAc binds most efficiently to Pd3(OAc)6 and forms active Cs2Pd2(OAc)6, lowering the tendency to leach Cs+. Reduction of Pd in M2Pd2(OAc)6 to a mixed "Pd/M+-O" adlayer on the bimetallic PdAu particles stabilized active Pd0 on the PdAu surface maintaining the catalyst activity. Thus, increasing "Pd/M+-O" concentrations from LiOAc to CsOAc lower long-term deactivation of PdAu.

KW - Absorption/extinction coefficient

KW - CO adsorption

KW - Dynamic reordering of silica supported Pd-Au alloy particles

KW - EXAFS

KW - In situ IR spectroscopy

UR - https://www.scopus.com/pages/publications/84947997385

U2 - 10.1016/j.jcat.2015.10.019

DO - 10.1016/j.jcat.2015.10.019

M3 - Article

AN - SCOPUS:84947997385

SN - 0021-9517

VL - 333

SP - 71

EP - 77

JO - Journal of Catalysis

JF - Journal of Catalysis

ER -

Impact of alkali acetate promoters on the dynamic ordering of PdAu catalysts during vinyl acetate synthesis

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Keywords

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