ZnxCd1-xS nanoparticles have been successfully synthesized by reaction of a single precursor - a Zn,Cd,Al-containing layered double hydroxide (ZnCdAl-LDH) - with H2S. The ZnxCd1-xS nanoparticles are homogeneously distributed within the confinement of an amorphous alumina matrix, in marked contrast to the aggregation that occurs with ZnxCd1-xS prepared by conventional coprecipitation. The photoactivities of the ZnxCd1-xS nanoparticles for methylene blue (MB) photodegradation increased with decreasing Zn mole fraction x, and the best performance was achieved with a Zn mole fraction of 0.20. The ZnxCd1-xS materials exhibited significantly better photocatalytic performance than ZnxCd1-xS with the same composition obtained either by a coprecipitation method or by sulfuration of a physical mixture of Zn,Al-LDH and Cd,Al-LDH precursors. This suggests that the ordered arrangement on an atomic level of the metal cations within the LDH layers leads to a homogeneous array structure of the ZnxCd1-xS solid solution, which suppresses the recombination of photoexcited electrons and holes, leading to improved photocatalytic activity. Our method provides a way to fabricate new types of chalcogenide semiconductor photocatalysts which are active under illumination by visible light. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.