Hierarchical Cu-Mn/ZSM-5 with boosted activity and selectivity for n-butylamine destruction: Synergy of pore structure and surface acidity

Adjusting the catalytic degradation route of nitrogen-containing VOCs (NVOCs) is still a challenge as both the oxidation and reduction reactions are simultaneously involved. Herein, a series of hierarchical Cu-Mn/ZSM-5 materials with different pore structures and surface acidities were prepared via an impregnation method and adopted for catalytic n-butylamine destruction. Experimental results show that the CuMn/Z-2 sample has the highest activity and N₂ selectivity, over which n-butylamine can be totally decomposed at 280 °C with N₂ selectivity over 82%. The superior catalytic performance of CuMn/Z-2 is owing to its developed porosity (accelerating the oxidation process and inhibiting organic byproducts formation) and weak acidity (slight adsorption of NH₃ and preventing the formation of N₂O). In situ DRIFTS reveal that the catalytic destruction of n-butylamine over Cu-Mn/ZSM-5 obeys two parallel pathways of n-butylamine adsorbed on acidic sites with C-N cleavage and n-butylamine adsorbed on metal sites and oxidized to amide before alcohol.