Alkali-Free Hydrothermally Reconstructed NiAl Layered Double Hydroxides for Catalytic Transesterification

NiAl layered double hydroxides (LDHs) are promising bifunctional catalysts comprising tunable redox and Lewis acidic sites. However, most studies of LDH employ alkali hydroxide carbonate precipitants which may contaminate the final catalyst leach into reaction media. Here, we report an alkali-free route to prepare NixAl LDHs with a composition range x = 1.7 4.1 using (NH4)2CO3 NH4OH as precipitants. Activation by calcination–rehydration protocols reveal can be reconstructed under mild hydrothermal treatment (110 °C for 12 h), degree reconstruction increasing Ni content. Catalyst activity tributyrin transesterification methanol was found increase content corresponding base site loadings; TOFs also increased, suggesting that sites in more effective transesterification. Hydrothermally Ni4.1Al active C4–C12 triglycerides stable towards leaching during