Highly active SBA-15-confined Pd catalyst with short rod-like micro-mesoporous hybrid nanostructure for n-butylamine low-temperature destruction

Abstract

Catalytic destruction of nitrogen-containing volatile organic compounds (NVOCs) is rarely reported although they can make great harm to the environment and public health. In the present work, a series of short rod-like micro-mesoporous composite SBA-15 materials (SBA-15-r) with developed porosity and enhanced mass transfer performance were rationally designed and synthesized, and highly dispersed and thermally stable Pd nanoparticles were successfully introduced into the mesopore channels of SBA-15-r via an extraordinary incipient wetness impregnation with the assistance of furfuryl alcohol and trimethylbenzene. The correlation between catalyst property and catalytic performance in n-butylamine destruction was elucidated. 29Si MAS NMR and FT-IR results show that phosphorus is incorporated into the skeleton of SBA-15-r through a POSi connection, altering the structural property of support. All Pd/SBA-15-r materials are highly active and stable catalysts with n-butylamine totally converted at 280 °C. Amongst, Pd/S-5 possesses the best n-butylamine oxidation activity and lowest NOx formation rate ascribable to the largest surface area and highest porosity which can promote the dispersion of Pd active sites and accelerate the oxidation process and product diffusion, inhibiting the formation of reaction byproducts. Moreover, the structural micropores over Pd/SBA-15-r catalysts play an important positive role in NOx formation control. The n-butylamine destruction mechanism were further discussed according to the results of gas chromatography and in situ DRIFTS. We believe that the present work provides new insights into the design and application of high-efficient catalysts based on hierarchical materials in NVOC elimination.