Fe, Co and Cu-incorporated TUD-1: Synthesis, characterization and catalytic performance in N2O decomposition and cyclohexane oxidation

Fe, Co and Cu-TUD-1 were prepared with different metal loadings (Si/M ratio = 100, 50, 20 and 10). As a function of increasing metal loading either isolated metal atoms, nano-particles of M-oxide and/or bulk M-oxide crystals in the silicate matrix were obtained, respectively. The materials were fully characterized by means of XRD, UV-vis, elemental analysis, N2 sorption measurements and HR-TEM. The catalytic performance of the prepared materials was tested in gas phase N2O decomposition and in liquid phase oxidation of cyclohexane. Results of N2O decomposition showed that a low M-loading is beneficial for the catalysis and leads to a high TOF, Co-TUD-1 being the most active catalyst. This suggests that the nano-particles observed in many catalysts are not dominating the N2O decomposition rate, and that active phase entities ranging from isolated to polynuclear sites are the most active. The performance of the TUD-1 catalysts is significantly lower than reported for the microporous Fe, Co and Cu analogues. In the oxidation of cyclohexane with TBHP, Cu-TUD-1 showed the highest activity but also significant leaching. Co-TUD-1 did not show any leaching and is thus the best applicable catalyst in cyclohexane oxidation.