Core-shell In/H-Beta@Ce catalyst with enhanced sulfur and water tolerance for selective catalytic reduction of NO_x by CH₄

A series of core-shell In/H-Beta@Ce catalysts were synthesized by encapsulating In/H-Beta within an amorphous CeO₂ shell and then evaluated for the selective catalytic reduction of NO_x by CH₄ (CH₄-SCR) under challenging conditions with SO₂ and H₂O. IB@Ce-2 achieved 57.7 % NO_x conversion at 625°C, representing a 23.0 % improvement over In/H-Beta (35.0 %) under similar no-optimized conditions. Under optimized conditions, it further achieved 97.5 % NO_x conversion at 600°C. Durability tests for IB@Ce-2 under optimized conditions showed NO_x conversion decreased from 97.5 % to 52.7 % over three cycles, while long-term operation maintained over 70 % conversion for 60 minutes. The amorphous CeO₂ shell enhanced SO₂ and H₂O tolerance by shielding InO⁺ active sites, facilitating redox cycling, and limiting sulfate formation. These findings highlight IB@Ce-2 as a durable and efficient candidate for NO_x abatement in natural gas vehicles and other real-world applications.