Thermal decomposition of platinum hexachloroplatinate (PtCl62-)-intercalated hydrotalcite (HT)-like solid, Mg0.74Al0.26(OH)(2)(NO3)(0.26), was carried out in the presence of H-2 or O-2 as a function of temperature. In a stream of H-2, metallic platinum deposited in the interlayer was found to catalytically reduce nitrate (NO3-) to N-2/N2O so as to give rise to a large surface area Pt-HT tranocomposite with micro/mesoporous structure at a lower temperature of 300 degreesC. By contrast, the pristine HT needs to be heated at greater than or equal to 400 degreesC to produce the porous structure. The Pt-HT composites showed the pore size distribution much narrower than the product obtained from "pristine HT. (C) 2004 Elsevier B.V. All rights reserved.