Revealing the Key Role of Acidic Oxygen-Containing Groups on Activated Carbon for Low-Temperature NH3-SCR Denitration

Simultaneous desulfurization and denitration by using activated coke is one of the most competitive technologies for cleaning low-temperature steel flue gases. The key to denitration performance relies on the regulation of active groups on the catalyst. In this work, the carboxyl and lactone groups with (NH 4 ) 2 S 2 O 8 oxidation and thermal treatment were found to mainly determined the catalytic activity. The results showed that (NH 4 ) 2 S 2 O 8 -treated AC catalyst improved denitration activity at low temperatures, which was attributed to the increase in oxygen-containing groups of the AC, the thermal treatment enhanced the low-temperature activity while reduced the performance in (210–240 ℃). According to the characterization results and conformational relationship analysis, we revealed that the adsorption and activation of NH 3 mainly depended on carboxyl groups during the middle-temperature range (210–240 ℃) NH 3 –SCR. Based on the advantage of middle-temperature denitration activity of modified activated coke, the carboxyl groups on activated coke were the most important active sites for the NH 3 –SCR reaction. Moreover, lactone groups, improved the denitration performance via promoting NO oxidation at low-temperatures range (120–150 ℃). However, the presence of only lactone groups in the 210–240 ℃ is not beneficial for the further promotion for denitration activity. This work initially reveals the decisive role of carboxyl and lactones groups of activated coke for the low-temperature NH 3 -SCR reaction, and guides the industrial arrangement of oxidation-modified AC as denitration catalyst. Graphical