TY - JOUR
T1 - An update on the mechanism of the graphene-NO reaction
AU - Oyarzún, Andrea M.
AU - Radovic, Ljubisa R.
AU - Kyotani, Takashi
N1 - Funding Information:
This study was supported by CONICYT-Chile , grants 1120609 and PFB-27 (CCTE-UDT), as well as a PhD scholarship to A.O. We are grateful to the reviewers, whose constructive criticism and comments helped us to clarify some of the ambiguities in the initial submission.
Publisher Copyright:
© 2015 Elsevier Ltd. All rights reserved.
PY - 2015/5/1
Y1 - 2015/5/1
N2 - Abstract Cognizant of the key experimental facts from studies of carbonaceous solids ranging from soot to graphite, we performed a quantum chemistry study of the interaction of NO monomer or dimer with one or more zigzag sites. Thermodynamic and kinetic results were used to examine two alternative mechanisms proposed in the literature, and to compare them with the graphene-O2 reaction mechanism. The chemisorption stoichiometry similarities are striking; but the differences, especially regarding the intermediate role of N2O, have important practical implications. Monomer chemisorption on an isolated site is a dead-end and temporarily inhibiting process, similar to that of formation of a stable C-O surface complex in the graphene-O2 reaction. When two sites are available, successive monomer adsorption eventually leads to N2O formation subsequent to parallel reorientation of the first NO molecule. If three contiguous sites are available, N2 and CO are the principal products. Chemisorption of the dimer provides a straightforward path to N2 and CO2 when one site is available and to N2 and CO when two sites are available. The formation of N2O is also feasible in this case, both during adsorption and desorption; in the adsorption phase it is very sensitive to the details of the electron pairing processes.
AB - Abstract Cognizant of the key experimental facts from studies of carbonaceous solids ranging from soot to graphite, we performed a quantum chemistry study of the interaction of NO monomer or dimer with one or more zigzag sites. Thermodynamic and kinetic results were used to examine two alternative mechanisms proposed in the literature, and to compare them with the graphene-O2 reaction mechanism. The chemisorption stoichiometry similarities are striking; but the differences, especially regarding the intermediate role of N2O, have important practical implications. Monomer chemisorption on an isolated site is a dead-end and temporarily inhibiting process, similar to that of formation of a stable C-O surface complex in the graphene-O2 reaction. When two sites are available, successive monomer adsorption eventually leads to N2O formation subsequent to parallel reorientation of the first NO molecule. If three contiguous sites are available, N2 and CO are the principal products. Chemisorption of the dimer provides a straightforward path to N2 and CO2 when one site is available and to N2 and CO when two sites are available. The formation of N2O is also feasible in this case, both during adsorption and desorption; in the adsorption phase it is very sensitive to the details of the electron pairing processes.
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U2 - 10.1016/j.carbon.2015.01.020
DO - 10.1016/j.carbon.2015.01.020
M3 - Article
AN - SCOPUS:84924576980
VL - 86
SP - 58
EP - 68
JO - Carbon
JF - Carbon
SN - 0008-6223
M1 - 9644
ER -