Characterisation of the active sites in mixed oxides derived from LDH precursors by physico-chemical and catalytic techniques

Catlytic conversion of 4-methyl-pentan-2-ol (MPO) was investigated over oxidic materials obtained by the calcination of MgNiCuAl layered double hydroxide (LDH) precursors. Keeping constant the M2+/M3+ ratio equal to 2 (where M2+ = Mg2+,Cu2+,Ni2+ and M3+= Al3+) various compositions of LDHs were prepared and characterised by X-ray diffraction (XRD), inductively coupled plasma (ICP), N2 adsorption/desorption and X-ray photoelectron spectra (XPS). The acid-base properties have been investigated by the means of physico-chemical methods such as microcalorimetry, by using ammonia (for acid sites) and carbon dioxide (for base sites) as probe molecules. The conversion of MPO was chosen as test reaction to investigate the catalytic activity and selectivity of the oxidic materials obtained by the calcination of MgNiCuAl LDHs and to correlate them with the acid-base properties of th eoxide surfaces. Copper was found to increase the alcohol dehydrogenation.