Microwave plasma decomposition of metal carbonyls has been used to syn
thesize a series of carbon-supported monometallic (Fe, Co) and bimetal
lic (Go-Mo) materials. The average metal particle diameters in all cas
es were less than 10 nm. By using 10% H-2/Ar instead of pure Ar as a c
arrier gas, the mean particle diameters could be decreased to less tha
n 2 nm. Although the distribution of particles is slightly broader tha
n those generated by other nanoparticle synthesis methods, the mean di
ameter of the particles generated using 10% H-2/Ar is as small as any
previously reported for Fe-, Co-, Ni-, or Mo-containing compounds. The
ultrafine metal particles were dispersed on moderate surface area amo
rphous carbon support matrixes derived from the concomitant microwave
decomposition of the toluene solvent.