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Title: Formic Acid Dissociative Adsorption on NiO(111): Energetics and Structure of Adsorbed Formate

Abstract

Here, the dissociative adsorption of carboxylic acids on oxide surfaces is important for understanding adsorbed carboxylates, which are important as intermediates in catalytic reactions, for the organo-functionalization of oxide surfaces, and in many other aspects of oxide surface chemistry. We present here the first direct experimental measurement of the heat of dissociative adsorption of any carboxylic acid on any single-crystal oxide surface. The enthalpy of the dissociative adsorption of formic acid, the simplest carboxylic acid, to produce adsorbed formate and hydrogen (as a surface hydroxyl) on a (2 × 2)-NiO(111) surface is measured by single crystal adsorption calorimetry. The differential heat of adsorption decreases with formic acid coverage from 202 to 99 kJ/mol at saturation (0.25 ML). The structure of the adsorbed products is clarified by density functional theory (DFT) calculations, which provide energies in reasonable agreement with the calorimetry. These calculations show that formic acid readily dissociates on both the oxygen and Ni terminations of the octapolar NiO(111) surfaces, donating its acid H to a surface lattice oxygen, while HCOO adsorbs preferentially with bridging-type geometry near the M-O3/O-M3 sites. The calculated energetics at low coverages agrees well with experimental data, while larger differences are observed at high coverage (0.25more » ML). The large decrease in experimental heat of adsorption with coverage can be brought into agreement with the DFT energies if we assume that both types of octapolar surface terminations (O- and Ni-) are present on the starting surface.« less

Authors:
ORCiD logo [1];  [2];  [1];  [3];  [2]; ORCiD logo [1]
  1. Univ. of Washington, Seattle, WA (United States)
  2. Stanford Univ., Stanford, CA (United States)
  3. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1457142
Alternate Identifier(s):
OSTI ID: 1483645
Grant/Contract Number:  
AC02-76SF00515; AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 121; Journal Issue: 50; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Zhao, Wei, Doyle, Andrew D., Morgan, Sawyer E., Bajdich, Michal, Norskov, Jens K., and Campbell, Charles T. Formic Acid Dissociative Adsorption on NiO(111): Energetics and Structure of Adsorbed Formate. United States: N. p., 2017. Web. doi:10.1021/acs.jpcc.7b09405.
Zhao, Wei, Doyle, Andrew D., Morgan, Sawyer E., Bajdich, Michal, Norskov, Jens K., & Campbell, Charles T. Formic Acid Dissociative Adsorption on NiO(111): Energetics and Structure of Adsorbed Formate. United States. doi:10.1021/acs.jpcc.7b09405.
Zhao, Wei, Doyle, Andrew D., Morgan, Sawyer E., Bajdich, Michal, Norskov, Jens K., and Campbell, Charles T. Tue . "Formic Acid Dissociative Adsorption on NiO(111): Energetics and Structure of Adsorbed Formate". United States. doi:10.1021/acs.jpcc.7b09405. https://www.osti.gov/servlets/purl/1457142.
@article{osti_1457142,
title = {Formic Acid Dissociative Adsorption on NiO(111): Energetics and Structure of Adsorbed Formate},
author = {Zhao, Wei and Doyle, Andrew D. and Morgan, Sawyer E. and Bajdich, Michal and Norskov, Jens K. and Campbell, Charles T.},
abstractNote = {Here, the dissociative adsorption of carboxylic acids on oxide surfaces is important for understanding adsorbed carboxylates, which are important as intermediates in catalytic reactions, for the organo-functionalization of oxide surfaces, and in many other aspects of oxide surface chemistry. We present here the first direct experimental measurement of the heat of dissociative adsorption of any carboxylic acid on any single-crystal oxide surface. The enthalpy of the dissociative adsorption of formic acid, the simplest carboxylic acid, to produce adsorbed formate and hydrogen (as a surface hydroxyl) on a (2 × 2)-NiO(111) surface is measured by single crystal adsorption calorimetry. The differential heat of adsorption decreases with formic acid coverage from 202 to 99 kJ/mol at saturation (0.25 ML). The structure of the adsorbed products is clarified by density functional theory (DFT) calculations, which provide energies in reasonable agreement with the calorimetry. These calculations show that formic acid readily dissociates on both the oxygen and Ni terminations of the octapolar NiO(111) surfaces, donating its acid H to a surface lattice oxygen, while HCOO adsorbs preferentially with bridging-type geometry near the M-O3/O-M3 sites. The calculated energetics at low coverages agrees well with experimental data, while larger differences are observed at high coverage (0.25 ML). The large decrease in experimental heat of adsorption with coverage can be brought into agreement with the DFT energies if we assume that both types of octapolar surface terminations (O- and Ni-) are present on the starting surface.},
doi = {10.1021/acs.jpcc.7b09405},
journal = {Journal of Physical Chemistry. C},
number = 50,
volume = 121,
place = {United States},
year = {2017},
month = {11}
}

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