Synergistic catalysis effect of Mn-promoted BaAl2O4 catalysts on catalytic performance for soot combustion

•Catalysts containing Mn exhibited high surface area and good redox property.•The Mn addition promoted drastically the catalytic performance for soot combustion.•An optimized catalyst must accommodate barium and manganese with proper balance.•The enhanced catalytic activity related with synergistic effect between Mn and Ba.

ABSTRACTA series of Mn-promoted BaAl2O4 catalysts were developed for catalytic soot combustion. These catalysts were characterized using XRD, BET, H2-TPR, O2-TPD, and in-situ DRIFTS. The results showed that an optimized combustion catalyst should accommodate barium and manganese with proper balance to promote soot combustion. A synergistic mechanism was suggested to explain the synergistic effect of manganese and barium: NO was trapped mainly as nitrites by barium, while the generated nitrites further transformed to nitrates facilitated by manganese, which finally oxidized soot into CO2.

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