Exploring an alternative route for meixnerite synthesis. The impact of the gaseous environment on the reconstruction of the lamellar structure and the catalytic performances

Abstract This work investigates the possibility to obtain the meixnerite structure Mg 6 Al 2 (OH) 18 ·4H 2 O in carbonate-free environment by direct co-precipitation of Mg and Al nitrates using only NaOH solution as precipitation agent as well as the physico-chemical and catalytic performances of the mixed oxide (MO) obtained by thermal decomposition of this layered material at 460 °C under nitrogen flow. The influence played by different gaseous environments, air or nitrogen, during the hydration of the above mentioned mixed oxide on the structural characteristics and catalytic performances of the derived reconstructed layered double hydroxide (LDH) materials (RLDH-A and RLDH-N, respectively) is also scrutinized. The characterization of the solids was performed by chemical and elemental analyses, XRD, DRIFTS, N 2 adsorption–desorption isotherms and adsorption of molecules with different pK a in order to determine their basicity. The catalytic activity for cyanoethylation was discussed in relation with the structural properties of the catalytic materials. The results showed that the co-precipitation method employed leads to the formation of an LDH containing also NO 3 − and CO 3 2 − anions besides HO − . Also, low amounts of C and N ( − base sites and is the most active for catalytic cyanoethylation.