Carbon nanotubes may be synthesised by chemical vapour deposition over supported Miffler clusters. A variety of both clusters and high surface area support materials were investigated. Molybdenum-only Muller clusters catalyse the synthesis of very limited amounts of multi-walled nanotubes whereas iron-molybdenum Muller clusters catalyse the synthesis of single-walled nanotubes when supported on alumina or magnesia. (c) 2006 Elsevier B.V. All rights reserved.