Promotional effect of SO2 on Cr2O3 catalysts for the marine NH3-SCR reaction

Cr2O3 catalysts for the marine NH3-selective catalytic reduction (NH3-SCR) reaction have been synthesized by precipitation, and their catalytic performances were evaluated. The experimental results revealed that the assynthesized Cr2O3 catalysts presented an enhanced NO removal efficiency when combined with SO2. Notably, the reaction efficiency increased from 61% to 94% with 100 ppm SO2 and from 61% to 82% with 500 ppm SO2 at 280 degrees C. The lifetime test confirmed the promotional effect of SO2 and the good sulfur and H2O resistance of Cr2O3, and the deactivation by SO2 proved to be irreversible. The NO removal efficiency remained at 89% after 28 h of reaction with 100 ppm SO2 and 3% H2O. The catalyst was characterized and the results confirmed eskolaite (Cr2O3) was successfully synthesized, the SCR reaction followed a Langmuir-Hinshelwood mechanism, and the increased SCR efficiency could mainly be attributed to the acid sites and O-a on the catalyst surface.