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Title: Single Pd atoms in activated carbon fibers and their contribution to hydrogen storage

Abstract

Palladium-modified activated carbon fibers (Pd-ACF) were synthesized by meltspinning, carbonization and activation of an isotropic pitch carbon precursor premixed with an organometallic Pd compound. The hydrogen uptake at 25 oC and 20 bar on Pd- ACF exceeded the expected capacity based solely on Pd hydride formation and hydrogen physisorption on the microporous carbon support. Aberration-corrected scanning transmission electron microscopy (STEM) with sub- ngstrom spatial resolution provided unambiguous identification of isolated Pd atoms occurring in the carbon matrix that coexist with larger Pd particles. First principles calculations revealed that each single Pd atom can form Kubas-type complexes by binding up to three H2 molecules in the pressure range of adsorption measurements. Based on Pd atom concentration determined from STEM images, the contribution of various mechanisms to the excess hydrogen uptake measured experimentally was evaluated. With consideration of Kubas binding as a viable mechanism (along with hydride formation and physisorption to carbon support) the role of hydrogen spillover in this system may be smaller than previously thought.

Authors:
 [1];  [1];  [2];  [3];  [1];  [2];  [1]
  1. ORNL
  2. Virginia Commonwealth University, Richland
  3. University of California, Davis
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1018976
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Carbon
Additional Journal Information:
Journal Volume: 49; Journal Issue: 12; Journal ID: ISSN 0008-6223
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; ACTIVATED CARBON; ADSORPTION; ATOMS; CAPACITY; CARBON; CARBONIZATION; FIBERS; HYDRIDES; HYDROGEN; HYDROGEN STORAGE; PRECURSOR; PRESSURE RANGE; SPATIAL RESOLUTION; TRANSMISSION ELECTRON MICROSCOPY; hydrogen storage; spillover; palladium; carbon fibers; Kubas complexes; single atoms

Citation Formats

Contescu, Cristian I, van Benthem, Klaus, Li, Sa, Bonifacio, Cecile S, Pennycook, Stephen J, Jena, Puru, and Gallego, Nidia C. Single Pd atoms in activated carbon fibers and their contribution to hydrogen storage. United States: N. p., 2011. Web. doi:10.1016/j.carbon.2011.05.021.
Contescu, Cristian I, van Benthem, Klaus, Li, Sa, Bonifacio, Cecile S, Pennycook, Stephen J, Jena, Puru, & Gallego, Nidia C. Single Pd atoms in activated carbon fibers and their contribution to hydrogen storage. United States. https://doi.org/10.1016/j.carbon.2011.05.021
Contescu, Cristian I, van Benthem, Klaus, Li, Sa, Bonifacio, Cecile S, Pennycook, Stephen J, Jena, Puru, and Gallego, Nidia C. 2011. "Single Pd atoms in activated carbon fibers and their contribution to hydrogen storage". United States. https://doi.org/10.1016/j.carbon.2011.05.021.
@article{osti_1018976,
title = {Single Pd atoms in activated carbon fibers and their contribution to hydrogen storage},
author = {Contescu, Cristian I and van Benthem, Klaus and Li, Sa and Bonifacio, Cecile S and Pennycook, Stephen J and Jena, Puru and Gallego, Nidia C},
abstractNote = {Palladium-modified activated carbon fibers (Pd-ACF) were synthesized by meltspinning, carbonization and activation of an isotropic pitch carbon precursor premixed with an organometallic Pd compound. The hydrogen uptake at 25 oC and 20 bar on Pd- ACF exceeded the expected capacity based solely on Pd hydride formation and hydrogen physisorption on the microporous carbon support. Aberration-corrected scanning transmission electron microscopy (STEM) with sub- ngstrom spatial resolution provided unambiguous identification of isolated Pd atoms occurring in the carbon matrix that coexist with larger Pd particles. First principles calculations revealed that each single Pd atom can form Kubas-type complexes by binding up to three H2 molecules in the pressure range of adsorption measurements. Based on Pd atom concentration determined from STEM images, the contribution of various mechanisms to the excess hydrogen uptake measured experimentally was evaluated. With consideration of Kubas binding as a viable mechanism (along with hydride formation and physisorption to carbon support) the role of hydrogen spillover in this system may be smaller than previously thought.},
doi = {10.1016/j.carbon.2011.05.021},
url = {https://www.osti.gov/biblio/1018976}, journal = {Carbon},
issn = {0008-6223},
number = 12,
volume = 49,
place = {United States},
year = {2011},
month = {1}
}