On the formation of hydrogen gas on copper in anoxic water
2011 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 135, no 8, 084709- p.Article in journal (Refereed) Published
Hydrogen gas has been detected in a closed system containing copper and pure anoxic water [P. Szakalos, G. Hultquist, and G. Wikmark, Electrochem. Solid-State Lett. 10, C63 (2007) and G. Hultquist, P. Szakalos, M. Graham, A. Belonoshko, G. Sproule, L. Grasjo, P. Dorogokupets, B. Danilov, T. Aastrup, G. Wikmark, G. Chuah, J. Eriksson, and A. Rosengren, Catal. Lett. 132, 311 (2009)]. Although bulk corrosion into any of the known phases of copper is thermodynamically forbidden, the present paper shows how surface reactions lead to the formation of hydrogen gas in limited amounts. While water cleavage on copper has been reported and investigated before, formation of molecular hydrogen at a single-crystal Cu surface is here explored using density functional theory and transition state theory. It is found that although solvent catalysis seems possible, the fastest route to the formation of molecular hydrogen is the direct combination of hydrogen atoms on the copper surface. The activation free energy (Delta G(s)double dagger(f)) of hydrogen formation in condensed phase is 0.70 eV, which corresponds to a rate constant of 10 s(-1) at 298.15 K, i.e., a relatively rapid process. It is estimated that at least 2.4 ng hydrogen gas could form per cm(2) on a perfect copper surface.
Place, publisher, year, edition, pages
2011. Vol. 135, no 8, 084709- p.
IdentifiersURN: urn:nbn:se:kth:diva-40660DOI: 10.1063/1.3624788ISI: 000294484700070ScopusID: 2-s2.0-80052417310OAI: oai:DiVA.org:kth-40660DiVA: diva2:443636
QC 20110926. Correction in: Journal of Chemical Physics, vol. 136, Issue 8. doi: 10.1063/1.36901522011-09-262011-09-202012-03-27Bibliographically approved