Catalytic purification of acrylonitrile-containing exhaust gases from petrochemical industry by metal-doped mesoporous zeolites

• A series of mesoporous catalysts was prepared and applied for SCC of acrylonitrile.
• Cu/SBA-15 exhibited excellent C2H3CN conversion activity and N2 selectivity.
• Two kinds of reaction mechanisms were proposed for Cu/, Fe/SBA-15 via DRIFTS.
• Supports with larger mesopores facilitated the dispersion of Cu2+ cations.
• SCC activity decreased along with the increasing hydrocarbon chains.

A series of metal catalysts with mesoporous zeolites as the supporters including Cu/, Co/, Fe/, Pt/SBA-15, Cu/SBA-16, and Cu/KIT-6 was prepared via impregnation method, and further characterized by N2 adsorption/desorption, XRD, XRF, TEM, XPS, and H2-TPR. The metallic cations were verified to be the main species over Cu/, Co/, Fe/SBA-15. CuO was largely formed over Cu/KIT-6 and Cu/SBA-16, while metallic Pt particles constituted the major species on Pt/SBA-15. The selective catalytic combustion (SCC) of acrylonitrile (C2H3CN) revealed that Cu/SBA-15 exhibiting a nearly complete C2H3CN conversion associated with N2 selectivity around 64% at T > 400 °C was the most promising catalyst. In comparison with the other mesoporous copper catalysts (Cu/KIT-6, Cu/SBA-16), the higher SCC activity of Cu/SBA-15 was attributed to its larger pore aperture greatly facilitating the copper dispersion. SCC mechanism for Cu/SBA-15 sample was further investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), revealing an oxidation mechanism.

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