PREPARATION OF SMALL COPPER PARTICLES OF HIGH CATALYTIC ACTIVITY USING A ROTATING CRYOSTAT

The rotating cryostat technique was used to trap small naked copper cl usters, Cu-n, n=3-7, and the copper carbonyls Cu-n(CO)(m), n=1-2, m=1- 6 in adamantane at 77 K. These clusters and carbonyls were then releas ed from the adamantane for incorporation into inert supports (Al2O3 an d SiO2) at low temperatures (110 K) by slowly dissolving the host adam antane matrix into an isopentane containing a slurry of the support. H ighly active catalysts for CO oxidation and CO/H-2 conversion to alkan es, alkenes and alcohols and with virtually unit dispersion were produ ced in this way. Efficient catalytic materials were also produced by d irectly implanting copper atoms into previously evaporated and condens ed sodium chloride layers. In this system the copper was embedded in n anocrystals of the halide of <8 nm diameter.