HTaWO6/(Pt,TiO2) and HTaWO6/(Pt,Fe2O3) nanocomposites were synthesized by successive intercalation reactions of HTaWO6 with [Pt(NH3)(4)]Cl-2 aqueous solution, n-C3H7NH2/n-heptane mixed solution and acidic TiO2 colloid solution or [Fe-3(CH3CO2)(7)(OH)(H2O)(2)]NO3 aqueous solution followed by UV light irradiation. The gallery heights of HTaWO6/(Pt,TiO2), HTaWO6/TiO2, HTaWO6/(Pt,Fe2O3) and HTaWO6/Fe2O3 was less than 0.51 nm. The host HTaWO6 was white possessing band gap energy of 3.1 eV, whereas HTaWO6/Pt, HTaWO6/(Pt,TiO2), HTaWO6/Fe2O3 and HTaWO6/(Pt,Fe2O3) were yellow and showed broad reflection over 400-600 nm together with that corresponding to the host layer. Photocatalytic activities of HTaWO6/TiO2 and HTaWO6/Fe2O3 were superior to those of unsupported TiO2 and Fe2O3 and were greatly enhanced by co-incorporation of Pt. HTaWO6/Pt, HTaWO6/(Pt,TiO2), HTaWO6/Fe2O3 and HTaWO6/(Pt,Fe2O3) showed photocatalytic activity. (C) 1999 Elsevier Science Ltd. All rights reserved.