TY - JOUR
T1 - Theoretical study of ammonia oxidation on platinum clusters - Adsorption of ammonia and water fragments
AU - Daramola, Damilola A.
AU - Botte, Gerardine G.
N1 - Funding Information:
The authors are thankful for the financial support of the Center for Electrochemical Engineering Research at Ohio University, and the Department of Defense through the US Army Construction Engineering Research Laboratory (W9132T-09-10001). The content of the information does not reflect the position or the policy of the US government. This research was also supported in part by the National Science Foundation through TeraGrid resources provided by the National Center for Supercomputing Applications under grant number TG-CTS100041.
PY - 2012/6/1
Y1 - 2012/6/1
N2 - This study examined the adsorption of reactants (NH 3 and OH) and intermediates (NH 2, NH, N and H 2O) formed during the oxidation of ammonia by hydroxyl on platinum. Specifically, four clusters were used to model the catalytic surface in the Pt(111) orientation. Structural, electronic and vibrational properties were calculated using Density Functional Theory (DFT). The molecules resided in the favored positions predicted by prior experimental observations and DFT calculations, while the adsorption energies followed the trend: H 2O<NH 3<OH<NH 2<NH<N, with the weakest bonds formed by charge transfer and the strongest bonds formed by orbital overlap of unpaired electrons of the radicals and the d orbital of adjacent Pt atoms. Calculated frequency vibrations in this work showed sufficient agreement with experimental observation, challenged previously assigned frequency modes for NH 2, NH and H 2O and predicted the correct shift in frequency vibrations upon adsorption on platinum when compared with prior DFT calculations.
AB - This study examined the adsorption of reactants (NH 3 and OH) and intermediates (NH 2, NH, N and H 2O) formed during the oxidation of ammonia by hydroxyl on platinum. Specifically, four clusters were used to model the catalytic surface in the Pt(111) orientation. Structural, electronic and vibrational properties were calculated using Density Functional Theory (DFT). The molecules resided in the favored positions predicted by prior experimental observations and DFT calculations, while the adsorption energies followed the trend: H 2O<NH 3<OH<NH 2<NH<N, with the weakest bonds formed by charge transfer and the strongest bonds formed by orbital overlap of unpaired electrons of the radicals and the d orbital of adjacent Pt atoms. Calculated frequency vibrations in this work showed sufficient agreement with experimental observation, challenged previously assigned frequency modes for NH 2, NH and H 2O and predicted the correct shift in frequency vibrations upon adsorption on platinum when compared with prior DFT calculations.
KW - Amide adsorption
KW - Ammonia adsorption
KW - Ammonia oxidation catalysis
KW - Density functional theory methods
KW - Hydrogen production
KW - Platinum catalyst
UR - http://www.scopus.com/inward/record.url?scp=84860469302&partnerID=8YFLogxK
U2 - 10.1016/j.comptc.2012.02.032
DO - 10.1016/j.comptc.2012.02.032
M3 - Article
AN - SCOPUS:84860469302
VL - 989
SP - 7
EP - 17
JO - Computational and Theoretical Chemistry
JF - Computational and Theoretical Chemistry
SN - 2210-271X
ER -