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Title: Kinetic Investigation of the Sustainable Electrocatalytic Hydrogenation of Benzaldehyde on Pd/C: Effect of Electrolyte Composition and Half-Cell Potentials

Abstract

The electrocatalytic reduction of benzaldehyde to benzyl alcohol on Pd supported on a carbon felt was conducted in the aqueous phase using a continuous flow fixed bed reactor at room temperature and atmospheric pressure. Methanol, ethanol, or isopropanol were added to the electrolyte to study the impact of alcohol type and concentration on the rates of benzaldehyde electrocatalytic hydrogenation and H2 evolution, the prevalent side reaction. Whereas the electrocatalytic hydrogenation rates and Faradaic efficiency decreased with increasing alcohol concentrations, the H2 evolution rates remained constant. The impact of the alcohol on hydrogenation was greater as the length of the alcohol’s hydrocarbon chain increased. Increasing the benzaldehyde concentration allows for high electrocatalytic hydrogenation rates, and high Faradaic efficiency. The reaction order increased from ~0.13 to ~0.66 with half-cell potential increasing from -650 mV to -1150 mV (vs. Ag/AgCl). A kinetic analysis reveals that the changes in reaction order are due to changes in benzaldehyde (and H) surface coverages as a function of half-cell cathodic potential. Thus, the results shown here reveal how the performance of the continuous electrocatalytic operation is affected by the electrolyte composition and half-cell cathodic potential.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Institute for Integrated Catalysis, Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, United States
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1489248
Report Number(s):
PNNL-SA-131189
Journal ID: ISSN 2168-0485
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
ACS Sustainable Chemistry & Engineering
Additional Journal Information:
Journal Volume: 6; Journal Issue: 12; Journal ID: ISSN 2168-0485
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
electrocatalytic reduction, alcohols, benzaldehyde, flow electrocatalytic cell, Pd

Citation Formats

Lopez-Ruiz, Juan A., Sanyal, Udishnu, Egbert, Jonathan, Gutiérrez, Oliver Y., and Holladay, Jamie. Kinetic Investigation of the Sustainable Electrocatalytic Hydrogenation of Benzaldehyde on Pd/C: Effect of Electrolyte Composition and Half-Cell Potentials. United States: N. p., 2018. Web. doi:10.1021/acssuschemeng.8b02637.
Lopez-Ruiz, Juan A., Sanyal, Udishnu, Egbert, Jonathan, Gutiérrez, Oliver Y., & Holladay, Jamie. Kinetic Investigation of the Sustainable Electrocatalytic Hydrogenation of Benzaldehyde on Pd/C: Effect of Electrolyte Composition and Half-Cell Potentials. United States. doi:10.1021/acssuschemeng.8b02637.
Lopez-Ruiz, Juan A., Sanyal, Udishnu, Egbert, Jonathan, Gutiérrez, Oliver Y., and Holladay, Jamie. Tue . "Kinetic Investigation of the Sustainable Electrocatalytic Hydrogenation of Benzaldehyde on Pd/C: Effect of Electrolyte Composition and Half-Cell Potentials". United States. doi:10.1021/acssuschemeng.8b02637.
@article{osti_1489248,
title = {Kinetic Investigation of the Sustainable Electrocatalytic Hydrogenation of Benzaldehyde on Pd/C: Effect of Electrolyte Composition and Half-Cell Potentials},
author = {Lopez-Ruiz, Juan A. and Sanyal, Udishnu and Egbert, Jonathan and Gutiérrez, Oliver Y. and Holladay, Jamie},
abstractNote = {The electrocatalytic reduction of benzaldehyde to benzyl alcohol on Pd supported on a carbon felt was conducted in the aqueous phase using a continuous flow fixed bed reactor at room temperature and atmospheric pressure. Methanol, ethanol, or isopropanol were added to the electrolyte to study the impact of alcohol type and concentration on the rates of benzaldehyde electrocatalytic hydrogenation and H2 evolution, the prevalent side reaction. Whereas the electrocatalytic hydrogenation rates and Faradaic efficiency decreased with increasing alcohol concentrations, the H2 evolution rates remained constant. The impact of the alcohol on hydrogenation was greater as the length of the alcohol’s hydrocarbon chain increased. Increasing the benzaldehyde concentration allows for high electrocatalytic hydrogenation rates, and high Faradaic efficiency. The reaction order increased from ~0.13 to ~0.66 with half-cell potential increasing from -650 mV to -1150 mV (vs. Ag/AgCl). A kinetic analysis reveals that the changes in reaction order are due to changes in benzaldehyde (and H) surface coverages as a function of half-cell cathodic potential. Thus, the results shown here reveal how the performance of the continuous electrocatalytic operation is affected by the electrolyte composition and half-cell cathodic potential.},
doi = {10.1021/acssuschemeng.8b02637},
journal = {ACS Sustainable Chemistry & Engineering},
issn = {2168-0485},
number = 12,
volume = 6,
place = {United States},
year = {2018},
month = {10}
}