Design and characterization of multi-component lamellar materials based on MWW-type zeolitic layers and metal oxide sub-domains

Abstract

The preparation of multi-component catalysts with tailored properties and high activity is essential for advancing sustainable catalytic processes and contributes to a healthy planet. In this study, we synthesised several families of multi-component materials by combining MWW-type zeolitic layers with MgAlCe oxide sub-domains at the nanometric scale, employing different approaches. Methods I and II involve the co-precipitation of MgAlCe LDH using various sources of Mg²⁺, Ce⁴⁺ and Al³⁺ in the presence of MWW zeolites. Method III utilizes swelling and intercalation of MWW with pre-formed LDH phases. After calcination, multi-component materials with integrated zeolitic layers and MgAlCe oxides were obtained, revealing significant structural differences across the methods. Method II allowed the co-precipitation of MgAlCe LDH sub-domains and promoted strong interactions between these LDH sub-domains and the MWW zeolite structure, disrupting regular LDH stacking. This interaction affects the structural organisation and results in inconsistently and irregularly stacked LDH layers, as shown by XRD patterns. Moreover, the presence of strong interactions with the zeolitic framework led to modify the chemical environment of the MWW structure. The characterization study revealed that these materials possess accessible acidic, basic, and redox sites, underscoring their potential as multi-functional catalysts. The homogeneous distribution of active sites within the porous zeolitic network would facilitate cooperative interactions between active centres of the zeolite structure and metallic oxides, while the small particle size and high dispersion of MgAlCe oxides should improve both the accessibility to these active sites and their number. Collectively, these structural and chemical properties make these multi-functional and component materials promising candidates for heterogeneous catalytic applications contributing to sustainable development and supporting efforts for a healthier planet.