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Title: Achieving High Selectivity for Alkyne Hydrogenation at High Conversions with Compositionally Optimized PdAu Nanoparticle Catalysts in Raspberry Colloid-Templated SiO 2

Abstract

Improving the selectivity for catalytic hydrogenation of alkynes is a key step in upgrading feedstocks for olefin polymerization. Herein, dilute Pd xAu 1-x alloy nanoparticles embedded in raspberry colloidtemplated silica (x = 0.02, 0.04, and 0.09) are demonstrated to be highly active and selective for the gas-phase hydrogenation of 1-hexyne, exhibiting higher selectivity than pure Pd at high conversion. The conversion of 1-hexyne remains high even for the very low amounts of Pd in Pd 0.02Au 0.98. These catalysts are highly resistant to sintering—addressing a long-standing challenge in the use of Au-based catalysts. Clear evidence is presented that the addition of the second hydrogen to the halfhydrogenated intermediate is the rate-limiting step, and that the stability of the half-hydrogenated intermediate of the alkyne is higher than the half-hydrogenated alkene which explains the high selectivity even at high conversions. Moreover, of the three compositions investigated, optimum selectivity and activity is observed for the nanoparticles containing 4% Pd. The apparent activation energy for production of 1-hexene from 1-hexyne is measured to be 38 kJ mol -1 for the Pd 0.04Au 0.96 catalysts, which is ~14 kJ mol -1 lower than for pure Pd. The hydrogenation is completely, but reversibly, suppressed by addingmore » CO to the reactant mixture, indicating that the Pd centers are the active sites for reaction. The method of templating used in preparation of the catalysts is highly customizable and versatile. As a result, this study demonstrates that the composition of the nanoparticles as defined by the dilution ratio of Pd in Au and by the method used to make the supported catalyst are important tunable parameters that can be used to optimize activity and selectivity of bimetallic systems.« less

Authors:
 [1];  [1]; ORCiD logo [2];  [3];  [4]; ORCiD logo [3]; ORCiD logo [2];  [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Harvard Univ., Cambridge, MA (United States)
  2. Univ. of Pennsylvania, Philadelphia, PA (United States)
  3. Univ. of California, Los Angeles, CA (United States)
  4. Harvard Univ., Cambridge, MA (United States); Utrecht Univ. (The Netherlands)
Publication Date:
Research Org.:
Harvard Univ., Cambridge, MA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1595073
Grant/Contract Number:  
SC0012573
Resource Type:
Accepted Manuscript
Journal Name:
ACS Catalysis
Additional Journal Information:
Journal Volume: 10; Journal Issue: 1; Journal ID: ISSN 2155-5435
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; selective alkyne hydrogenation; dilute alloy catalysts; PdAu supported on SiO2; colloidal templating; TEM; DFT

Citation Formats

Luneau, Mathilde, Shirman, Tanya, Foucher, Alexandre C., Duanmu, Kaining, Verbart, David M. A., Sautet, Philippe, Stach, Eric A., Aizenberg, Joanna, Madix, Robert J., and Friend, Cynthia M. Achieving High Selectivity for Alkyne Hydrogenation at High Conversions with Compositionally Optimized PdAu Nanoparticle Catalysts in Raspberry Colloid-Templated SiO2. United States: N. p., 2019. Web. doi:10.1021/acscatal.9b04243.
Luneau, Mathilde, Shirman, Tanya, Foucher, Alexandre C., Duanmu, Kaining, Verbart, David M. A., Sautet, Philippe, Stach, Eric A., Aizenberg, Joanna, Madix, Robert J., & Friend, Cynthia M. Achieving High Selectivity for Alkyne Hydrogenation at High Conversions with Compositionally Optimized PdAu Nanoparticle Catalysts in Raspberry Colloid-Templated SiO2. United States. doi:10.1021/acscatal.9b04243.
Luneau, Mathilde, Shirman, Tanya, Foucher, Alexandre C., Duanmu, Kaining, Verbart, David M. A., Sautet, Philippe, Stach, Eric A., Aizenberg, Joanna, Madix, Robert J., and Friend, Cynthia M. Thu . "Achieving High Selectivity for Alkyne Hydrogenation at High Conversions with Compositionally Optimized PdAu Nanoparticle Catalysts in Raspberry Colloid-Templated SiO2". United States. doi:10.1021/acscatal.9b04243.
@article{osti_1595073,
title = {Achieving High Selectivity for Alkyne Hydrogenation at High Conversions with Compositionally Optimized PdAu Nanoparticle Catalysts in Raspberry Colloid-Templated SiO2},
author = {Luneau, Mathilde and Shirman, Tanya and Foucher, Alexandre C. and Duanmu, Kaining and Verbart, David M. A. and Sautet, Philippe and Stach, Eric A. and Aizenberg, Joanna and Madix, Robert J. and Friend, Cynthia M.},
abstractNote = {Improving the selectivity for catalytic hydrogenation of alkynes is a key step in upgrading feedstocks for olefin polymerization. Herein, dilute PdxAu1-x alloy nanoparticles embedded in raspberry colloidtemplated silica (x = 0.02, 0.04, and 0.09) are demonstrated to be highly active and selective for the gas-phase hydrogenation of 1-hexyne, exhibiting higher selectivity than pure Pd at high conversion. The conversion of 1-hexyne remains high even for the very low amounts of Pd in Pd0.02Au0.98. These catalysts are highly resistant to sintering—addressing a long-standing challenge in the use of Au-based catalysts. Clear evidence is presented that the addition of the second hydrogen to the halfhydrogenated intermediate is the rate-limiting step, and that the stability of the half-hydrogenated intermediate of the alkyne is higher than the half-hydrogenated alkene which explains the high selectivity even at high conversions. Moreover, of the three compositions investigated, optimum selectivity and activity is observed for the nanoparticles containing 4% Pd. The apparent activation energy for production of 1-hexene from 1-hexyne is measured to be 38 kJ mol-1 for the Pd0.04Au0.96 catalysts, which is ~14 kJ mol-1 lower than for pure Pd. The hydrogenation is completely, but reversibly, suppressed by adding CO to the reactant mixture, indicating that the Pd centers are the active sites for reaction. The method of templating used in preparation of the catalysts is highly customizable and versatile. As a result, this study demonstrates that the composition of the nanoparticles as defined by the dilution ratio of Pd in Au and by the method used to make the supported catalyst are important tunable parameters that can be used to optimize activity and selectivity of bimetallic systems.},
doi = {10.1021/acscatal.9b04243},
journal = {ACS Catalysis},
number = 1,
volume = 10,
place = {United States},
year = {2019},
month = {11}
}

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