Selective catalytic reduction of NO using acetone solvent vapors as the reducing agent over Cu2+ and/or Al3+ ions substituted MCM-41 catalysts

• Bifunctional mesoporous Cu–Al–MCM-41 was synthesized by hydrothermal method.
• Cu–Al–MCM-41 was found to be effective catalyst for the NO reduction in the presence of acetone solvent vapors as reducing agent.
• Well dispersed and isolated Cu2+ ions on the mesoporous catalyst can act as an active redox centre in the VOC-SCR of NO.

Selective catalytic reduction (SCR) of nitrogen monoxide (NO) using acetone solvent vapors as the reducing agent over mesoporous Cu–MCM-41, Al–MCM-41, Cu–Al–MCM-41 and CuO supported metal oxides such as CuO/Al2O3 and CuO/SiO2 was investigated in this study. The synthesized materials were characterized by using powder low-angle X-ray diffraction (XRD), N2 adsorption–desorption measurements, 27Al magic angle spinning-nuclear magnetic resonance spectroscopy (MAS-NMR), electron paramagnetic resonance spectroscopy (EPR) and inductively coupled plasma-mass spectrometer (ICP-MS) analysis. The presence of isolated Cu2+ ions and tetrahedrally coordinated Al3+ ions within the framework of Cu–Al–MCM-41 catalyst played a vital role in this deNOx reaction as confirmed by EPR and 27Al MAS-NMR spectroscopic studies, respectively. Among the various catalysts studied, bifunctional Cu–Al–MCM-41 was found to be the most effective catalyst for achieving maximum deNOx activity at lower temperatures of around 250–350 °C. Besides, Cu–Al–MCM-41 catalyst also showed higher acetone oxidation than those of Cu–MCM-41, CuO/Al2O3 and CuO/SiO2 catalysts in the entire temperature range. For higher temperature of above 400 °C, it was found that Cu–MCM-41 catalyst shows highest activity for the NO reduction but it shows less acetone incineration activity as compared to that of Cu–Al–MCM-41 catalyst. The study of simultaneous removal of NO and acetone solvent vapors using Cu–Al–MCM-41 and Cu–MCM-41 catalysts reveals the potential of using waste organic solvents from industry as the reducing agent of deNOx (SCR) process.

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