Probing the chemical reactivity of the B2O3 -I (1 0 1) Surface: Interaction with H2O and H2S

Assaf, N.W., Altarawneh, M.ORCID: 0000-0002-2832-3886, Radny, M., Oluwoye, I.ORCID: 0000-0002-0221-020X and Dlugogorski, B.Z. (2022) Probing the chemical reactivity of the B2O3 -I (1 0 1) Surface: Interaction with H2O and H2S. Applied Surface Science, 599 . Art. 153999.

Abstract

Diboron trioxide is of interest because of its unique unreactive functionality properties. In this work we have studied – via computational first-principle techniques - the adsorption and dissociation mechanisms of two hydrogen chalcogenides, namely water (H2O) and hydrogen sulfide (H2S) molecules, over the B2O3 -I (1 0 1) surface. We show that the water molecules undergo dissociative adsorption over diboron via an activation energy of 39 kJ/mol. Furthermore, desorption of both molecularly adsorbed and dissociated structures of water molecules from the B2O3 -I (1 0 1) surface requires activation energies of 124–127 kJ/mol. Our investigation on the other hydrogen-chalcogenide compound, i.e. H2S, reveals that diboron trioxide attracts H2S molecules and forms molecular adsorption via sp3 hybridisation between the lone pair electron of the H2S and the empty p orbital of the Bsurf atom without encountering an activation barrier. However, the energy barrier required to dissociate H2S over the B2O3 -I (1 0 1) surface appears exceedingly high at 310 kJ/mol. The present insight resolves the two different behaviours of B2O3 concerning hydrogen chalcogenides reported in the literature. While acting as a water scavenger to generate dissociated radicals, it exhibits an inhibitor characteristic towards the dissociation of H2S molecules, representing an ideal reactor wall coating for desired pure gas phase reactions.

Item Type:	Journal Article
Murdoch Affiliation(s):	College of Science, Health, Engineering and Education
Publisher:	Elsevier BV
Copyright:	© 2022 Elsevier B.V.
URI:	http://researchrepository.murdoch.edu.au/id/eprint/65345

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