학술논문
Identification of Intermediates in the Reaction Pathway of SO2 on the CaO Surface: From Physisorption to Sulfite to Sulfate.
Document Type
Article
Author
Source
Subject
*FLUE gas desulfurization
*PHYSISORPTION
*ACID rain
*SURFACE chemistry
*REFLECTANCE spectroscopy
*DENSITY functional theory
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Language
ISSN
0947-6539
Abstract
The interaction of CaO and Ca(OH)2 with solvated or gaseous SO2 plays a crucial role in the corrosion of urban infrastructure by acid rain or in the removal of SO2 from flue gas. We carried out a combined spectroscopic and theoretical investigation on the interaction of SO2 with a CaO(001) single crystal. First, the surface chemistry of SO2 was investigated at different temperatures using polarization‐resolved IR reflection absorption spectroscopy. Three species were identified, and an in‐depth density functional theory study was carried out, which allowed deriving a consistent picture. Unexpectedly, low temperature exposure to SO2 solely yields a physisorbed species. Only above 100 K, the transformation of this weakly bound adsorbate first to a chemisorbed sulfite and then to a sulfate occurs, effectively passivatating the surface. Our results provide the basis for more efficient strategies in corrosion protection of urban infrastructure and in lime‐based desulfurization of flue gas. [ABSTRACT FROM AUTHOR]