TY - JOUR
T1 - Interaction of Oxygen with α-Rhombohedral Boron (001) Surface
AU - Assaf, Niveen W.
AU - Altarawneh, Mohammednoor K.
AU - Radny, Marian W.
AU - Jiang, Zhong Tao
AU - Dlugogorski, Bogdan Z.
N1 - Funding Information:
ACKNOWLEDGMENTS: This work has been supported by the Australian Research Council (ARC). The National Computational Infrastructure (NCI), Australia and Pawsey Supercomputing Centre in Perth are also acknowledged for grants of computing time. N.A. thanks Murdoch University for the award of a postgraduate scholarship. MWR acknowledges also the Polish Ministry of Science and Higher Education (06/62/DSPB/0216).
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/3/24
Y1 - 2016/3/24
N2 - This contribution presents a computational account of strong and exothermic interaction of atomic and molecular oxygen with the α(001)B12 surface of boron. Physisorbed oxygen interacts weakly with the surface, but the dissociative chemisorption entails considerable exothermicity in the range of 2.47-3.45 eV, depending on the adsorbed sites of the two oxygen atoms. Nonetheless, rupture of dioxygen on the surface involves a sizable intrinsic reaction barrier of 3.40 eV (at 0 K). Such high amount of energy clearly explains the chemical inertness (i.e., the lack of oxidation) of boron at room temperature. However, elevated temperature encountered in real applications of boron, such as cutting machinery, overcomes the high-energy barrier for the dissociative adsorption of molecular oxygen (3.40 eV). A stability T-P phase diagram reveals the spontaneous nature of the substitutional O/α(001)B12 adsorption modes that lead to the formation of diboron trioxide (B2O3) at temperatures and pressure pertinent to practical applications. This finding conclusively collaborates the experimental observation of the formation of the B2O3 phase from adsorption of oxygen on boron. Finally, charge analysis provides an atomic-scale probe for the predicted stability ordering of the considered O/α(001)B12 configurations.
AB - This contribution presents a computational account of strong and exothermic interaction of atomic and molecular oxygen with the α(001)B12 surface of boron. Physisorbed oxygen interacts weakly with the surface, but the dissociative chemisorption entails considerable exothermicity in the range of 2.47-3.45 eV, depending on the adsorbed sites of the two oxygen atoms. Nonetheless, rupture of dioxygen on the surface involves a sizable intrinsic reaction barrier of 3.40 eV (at 0 K). Such high amount of energy clearly explains the chemical inertness (i.e., the lack of oxidation) of boron at room temperature. However, elevated temperature encountered in real applications of boron, such as cutting machinery, overcomes the high-energy barrier for the dissociative adsorption of molecular oxygen (3.40 eV). A stability T-P phase diagram reveals the spontaneous nature of the substitutional O/α(001)B12 adsorption modes that lead to the formation of diboron trioxide (B2O3) at temperatures and pressure pertinent to practical applications. This finding conclusively collaborates the experimental observation of the formation of the B2O3 phase from adsorption of oxygen on boron. Finally, charge analysis provides an atomic-scale probe for the predicted stability ordering of the considered O/α(001)B12 configurations.
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U2 - 10.1021/acs.jpcc.5b09694
DO - 10.1021/acs.jpcc.5b09694
M3 - Article
AN - SCOPUS:84962130169
SN - 1932-7447
VL - 120
SP - 5968
EP - 5979
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 11
ER -