New Insights into the Decomposition Behavior of NH₄HSO₄ on the SiO₂-Decorated SCR Catalyst and Its Enhanced SO₂-Resistant Ability.

ABSTRACT: This article illustrates the detailed decomposition behavior of NH₄HSO₄ on the TiO₂ and TiO₂-SiO₂ supports, along with the effect of SiO₂ addition on the sulfur resistance of the corresponding V₂O₅-based catalysts. For TiO₂ support, sulfate species selectively occupied its surface basic hydroxyl groups, while Si-OH groups functioned as the main sites for the accommodation of NH₄HSO₄ over the TiO₂-SiO₂ mixed support, enabling its surface sulfate species with higher thermal stability. Compared with NH₄ ⁺ on the TiO₂ surface, NH₄ ⁺ on the TiO₂-SiO₂ mixed support was much easier to be consumed during the heating process, hence causing some variations in the decomposition behavior of NH₄HSO₄. Finally, adding SiO₂ enhanced the SO₂ tolerance properties of the catalysts to a certain extent. When exposed to the SO₂-containing flue gas, the deposition of NH₄HSO₄ mainly caused serious deactivation of SiO₂-free catalyst, while the as-accumulated SO₄ ^2- also contributed to the declined activity of SiO₂-added catalyst. These results ensured the potential commercialization of TiO₂-SiO₂-based catalysts in the typical low-temperature selective catalytic reduction systems in the short run and pointed out a strategy to design new catalysts with superior activity and enhanced SO₂-tolerant ability.

SUBMITTER: Ye D 

PROVIDER: S-EPMC6648227 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature