The preparation, characterization, activity, and stability of a Ni-Al2O3 catalyst derived from reduction of a Ni-Al layered double hydroxide precursor (LDH, Ni6Al2(OH)(16)(CO3)(0.75)(OH)(0.25)center dot 4H(2)O) are reported in this paper. In-situ X-ray adsorption spectroscopy shows that reduction of Ni from the LDH precursor to form a highly loaded 80% Ni-Al2O3 catalyst (Ni-Al2O3-LDH) is faster than reduction of a 10% impregnated Ni-Al2O3 alumina (Ni-Al2O3-I) catalyst. The reduced Ni-Al2O3-LDH catalyst exhibits highly dispersed Ni nanoparticles (3-5 nm) distributed on top, partially embedded nanoparticles, and some encapsulated in the Al2O3 matrix. The nanoparticles impregnated on alumina (Ni-Al2O3-I) are larger (similar to 7-15 nm) and appear on top of the alumina support. Conversion vs time on stream (TOS) results during ethanol decomposition at 250 degrees C on Ni-Al2O3-LDH exhibits only a slight deactivation during 100 h TOS, while the Ni-Al2O3-I catalyst shows rapid deactivation with no conversion after 2h TOS. X-ray photoelectron spectroscopy shows that the carbon content increases up to 48% after 100 h TOS on the Ni-Al2O3-LDH catalyst, while a similar increase occurs after 2 h TOS on the Ni-Al2O3-I catalyst. TEM shows that after 100 h TOS either a thin layer of amorphous carbon or carbon nanotubes forms on Ni on top of the alumina matrix and on partially embedded Ni nanoparticles on the Ni-Al2O3-LDH catalyst. Total surface area of the Ni-Al2O3-LDH catalyst increased during TOS, which may be suplying fresh surface Ni from the encapsulated Ni nanoparticles that sustain the high activity. (C) 2015 Elsevier B.V. All rights reserved.