Synthesis of nickel nanoparticles dispersed in γ-alumina by heterogeneous precipitation

A heterogeneous precipitation method is described for obtaining nanocomposite powders consisting of Ni nanoparticles homogeneously dispersed within gamma-Al2O3. The amorphous Al(OH)3 was nucleated on the surfaces of NiO nanoparticles and crystallized to gamma-Al2O3 at 900 degreesC. The porosity of gamma-Al2O3 allowed the growth of NiO nanoparticles during calcinations. After the calcined nanocomposite powders were selectively reduced at 700 degreesC in a hydrogen atmosphere, NiO nanoparticles were converted to Ni with the size of 25-35 nm. TEM observation and AES analysis showed Ni nanoparticles were uniformly dispersed in the gamma-Al2O3 matrix. (C) 2002 Elsevier Science Ltd and Techna S.r.l. All rights reserved.