Multi-component catalysts with integrated MWW-type layers and mixed oxide domains for glucose-to-formic acid oxidation

Abstract

The development of efficient and multi-component catalysts with distinct active sites is essential to promote chemically and economically circular processes and to achieve sustainable development. In this work, various multi-component materials were synthesized combining the properties of MWW zeolitic layers and MgAl mixed oxides. Synthesis conditions were successfully developed and optimized to achieve the in situ formation of nanometric sub-domains of layered double hydroxides (LDHs) on the surfaces and within the microporous cavities and channels of MWW layers (methods I and II). Additionally, multi-component materials were prepared by mixing MWW lamellar precursors and preformed layered double hydroxides, using swelling and exfoliation techniques and combined with sonification and ball-milling techniques (method III). Calcination yielded materials effectively integrating zeolitic MWW layers with MgAl oxides, displaying distinct structural features depending on the synthesis method. The catalytic performance of these materials was evaluated in the oxidation of glucose to formic acid (FA) using H₂O₂ as the oxidant. Among the catalysts investigated, MWW@MgAl-in situ-40, which combined suitable textural properties and basicity, showed superior activity, achieving a 47.7% FA yield at 66.2% glucose conversion after 7.5 h at 363 K in dioxane.