Abstract
A series of layered double hydroxides (LDH) with molar ratio M2⁺/M³ ⁺ = 3:1 and different degrees of aluminum substitution in the cationic sites by Ni3+ were prepared by precipitation from solution in the presence of sodium hypochlorite as an oxidizing agent. The synthesized samples were characterized by various techniques including powder X-ray Diffraction (XRD), Thermogravimetric and Differential Thermal Analysis (TG-DTA), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and inverse Temperature-programmed Reduction (iTPR). The results indicate that single-phase LDHs were formed during synthesis and they were of a high degree of crystallinity. The thermal stability of LDHs did not decrease essentially with increasing Ni3+ content. The calcination at 600 °C led to the complete destruction of the layered structure and formation of mixed oxide phases. In iTPR experiments for as-synthesized LDHs the reduction of Ni3+ to Ni2+ took place above 400 °C, and the reduction of Ni2+ to Ni° occurred above 600 °C.
Published Version
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