Microwave-treated layered double hydroxides containing Ni2+ and Al3+: The effect of added Zn2+

Ni containing layered double hydroxides (LDHs) have been prepared by precipitation and hydrothermally treated under microwave irradiation for different periods of time. The solids have been calcined at three temperatures corresponding to stable phases formed during thermal decomposition of LDHs. The properties of the irradiated samples and of the calcined products were studied in order to ascertain whether the ageing treatment under microwave irradiation modifies not only the properties of the layered materials, but also the properties of the calcined products. A structural and textural study was carried out by PXRD, FT-IR and Vis–UV spectroscopy, thermal analyses (DTA and TG), N2 adsorption/desorption at −196 °C and TEM microscopy; the reducibility of the nickel species was studied as well by TPR. The results show that the microwave treatment leads to better crystallized LDHs with modified thermal stability and reducibility. In addition, the degree of crystallinity of the layered precursors and their textural properties determine the properties of their thermal decomposition products.

Layered double hydroxides were prepared by the microwave-hydrothermal treatment. This method allows obtaining in short periods of time well crystallized LDHs with well-defined hexagonal-shaped particles, and improved thermal stability and the textural properties. In addition, the degree of crystallinity of the layered precursors and their textural properties determine the properties of their thermal decomposition products.Figure optionsDownload as PowerPoint slide