Like Cures like: Detoxification Effect between Alkali Metals and Sulfur over the V2O5/TiO2 deNOx Catalyst

The V2O5/TiO2 (VTi) catalyst has been widely employed for the NH3 selective catalytic reduction (NH3-SCR) reaction, and sulfur (S) and alkali metals (K) were usually considered as poisons during this reaction. In this work, the synergistic effect of S and K over the VTi catalyst for the NH3-SCR reaction was analyzed and discussed. It is surprisingly observed that the synergistic effects of S and K exhibited a detoxification effect on the NH3-SCR reaction. That is, although the VTi catalyst exhibited moderate resistance to S poisoning and unsatisfactory resistance to K deactivation, the SCR activity was restored to close to fresh VTi when K and S coexisted. This detoxification effect also could occur between other alkali metals (e.g., Ca and Na) and sulfur. X-ray photoelectron spectroscopy and charge density difference studies both indicate that the introduction of K could significantly affect the electronic structure of V, but this toxic effect was recovered by the further addition of S because of the strong interaction between S and K. Therefore, this detoxification effect can occur in the practical reaction atmosphere, which alleviates the alkali metal poisoning of commercial catalysts.

Automated summary

This study analyzes the synergistic effect of sulfur (S) and alkali metals (K) on the V2O5/TiO2 (VTi) catalyst for the NH3 selective catalytic reduction (NH3-SCR) reaction. It is found that the presence of S and K exhibits a detoxification effect, alleviating the alkali metal poisoning of commercial catalysts.