MgMoO4 particles prepared from combustion were used as precursor of Mo/MgO catalyst for the growth of multi-walled carbon nanotubes (MWCNTs). The results showed that MgMoO4 particles can break into small particles in a few seconds in the presence of H-2 at 1000 degrees C in an event similar to avalanche to form MgO particles enwrapped with Mo nanoparticles which favours the growth of nanotubes. The egregious high yield of the nanotubes up to 2000% after 40 min growth can be achieved for this specific catalyst system. A model called "avalanche-like reduction" of the MgMoO4 was proposed to explain the formation of high active Mo/MgO catalyst for the growth of nanotubes. (C) 2008 Published by Elsevier B.V.