In-situ DRIFTS study on the k-poisoning resistance mechanism of titanium bearing blast furnace slag catalyst by Sm/La doping

Benefiting from the construction of lamellar framework Sm-CeZrTiAl amorphous mixed oxides synthesized by the hydrothermal method, enhanced NH3-SCR performance over a wide temperature window for K poisoning resistance was observed. The Sm-CeZrTiAl catalyst preserved higher catalytic performance after K was introduced than the catalysts without added Sm, as it maintained > 90% NO conversion between 300 and 420 degrees C. The outstanding K poisoning-resistance of the Sm-CeZrTiAl catalyst could benefit from its good nano-Al2O3 flake skeleton structure, high specific surface area, and rich pore channels. In addition, Sm doping can effectively increase the number of surface acid sites, especially strong acid sites, which promote the formation of NOx adsorption species such as nitrite, bidentate nitrate and bridging nitrate intermediates and facilitate the conversion of NO to N2 by following the Langmuir-Hinshelwood mechanism. In addition, the synergy between Sm/ La and Ce leads to more Ce3+ and Bronsted acid sites. Through the redox cycle of Ce4++Sm2+-> Ce3++Sm3+ or Ce4++La2+-> Ce3++La3+, catalytic reduction can be realized with good performance. Moreover, a significant portion of K on the catalyst surface preferentially interacted with strong acidic sites provided by Sm/La doping, thereby preventing Ce species from poisoning and leaving them available for the catalytic cycle.

Automated summary

The hydrothermally synthesized lamellar framework Sm-CeZrTiAl amorphous mixed oxides exhibit enhanced NH3-SCR performance and improved resistance to K poisoning. The good nano-Al2O3 flake skeleton structure, high specific surface area, and rich pore channels contribute to the excellent K poisoning-resistance of the catalyst. Sm doping increases the number of surface acid sites, especially strong acid sites, promoting the conversion of NO to N2. The synergy between Sm/La and Ce facilitates catalytic reduction and prevents Ce species from being poisoned.