TY - JOUR
T1 - DFT calculations of ammonia oxidation reactions on bimetallic clusters of platinum and iridium
AU - Estejab, Ali
AU - Botte, Gerardine G.
N1 - Funding Information:
The authors would like to thank the financial support of the Center for Electrochemical Engineering Research at Ohio University and the Department of Defense through the U.S. Army Construction Engineering Research Laboratory ( W9132T-12-2-0006 ). They also would like to thank Dr. Damilola A. Daramola and Dr. Nancy Sandler for the fruitful discussions, time and general help they provided in this project. This research was also supported in part by the Ohio Supercomputer Center under grant number OSC-PHS0269 . The content of the information does not reflect the position or the policy of the U.S. government.
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/9/1
Y1 - 2016/9/1
N2 - Density functional theory calculations were performed on four platinum-iridium clusters, Pt3-xIrx (x = 0-3) to examine ammonia oxidation in alkaline media. The adsorption of NH3-x (x = 0-3) on these clusters and the effect of cluster composition on the adsorption were investigated. The hybrid B3LYP level of theory was used in Gaussian 09 along with the LANL2DZ and 6-311++g basis sets.The HOMO-LUMO energy gap on bare metal clusters showed that increasing the iridium concentration decreased the energy gap, a sign of a more reactive catalyst. The relative adsorption energy showed more stability of NH3-x on the Ir3 cluster and less stability as the number of platinum atoms increased in the cluster. These results combined with activation and dissociation energy calculations of sequential dehydrogenation reactions showed that Ir3 is more active than Pt3 for ammonia oxidation, and the addition of iridium to platinum makes a more favorable pathway for the ammonia oxidation reaction. The computational calculations suggest the possibility of two different mechanisms of ammonia oxidation on platinum and iridium electrocatalysts.
AB - Density functional theory calculations were performed on four platinum-iridium clusters, Pt3-xIrx (x = 0-3) to examine ammonia oxidation in alkaline media. The adsorption of NH3-x (x = 0-3) on these clusters and the effect of cluster composition on the adsorption were investigated. The hybrid B3LYP level of theory was used in Gaussian 09 along with the LANL2DZ and 6-311++g basis sets.The HOMO-LUMO energy gap on bare metal clusters showed that increasing the iridium concentration decreased the energy gap, a sign of a more reactive catalyst. The relative adsorption energy showed more stability of NH3-x on the Ir3 cluster and less stability as the number of platinum atoms increased in the cluster. These results combined with activation and dissociation energy calculations of sequential dehydrogenation reactions showed that Ir3 is more active than Pt3 for ammonia oxidation, and the addition of iridium to platinum makes a more favorable pathway for the ammonia oxidation reaction. The computational calculations suggest the possibility of two different mechanisms of ammonia oxidation on platinum and iridium electrocatalysts.
KW - Ammonia electrolysis
KW - Ammonia oxidation
KW - Density functional theory
KW - Hydrogen production
KW - Platinum and iridium bimetallic catalyst
KW - Waste water remediation
UR - http://www.scopus.com/inward/record.url?scp=84978120377&partnerID=8YFLogxK
U2 - 10.1016/j.comptc.2016.06.030
DO - 10.1016/j.comptc.2016.06.030
M3 - Article
AN - SCOPUS:84978120377
SN - 2210-271X
VL - 1091
SP - 31
EP - 40
JO - Computational and Theoretical Chemistry
JF - Computational and Theoretical Chemistry
ER -