Chemical and catalytic activity of copper nanoparticles prepared via metal vapor synthesis

Nanocrystalline particles of copper have been prepared using the solvated metal atom dispersion (SMAD) technique. Their chemical and catalytic reactivity have been tested in the Ullman reaction (aryl homocoupling) and the hydrogenation of CO 2 to form CH 3 OH. The powders obtained from different solvents have surface areas of 24–30 m 2 /g, particle sizes of 20–45 nm, and crystallite sizes of 8–12 nm. The order of activity found toward the aryl homocoupling reaction is Cu * /toluene > Cu * /THF > Cu * /pentane > Cu * /diglyme, with a maximum biphenyl yield of 90% at 150 °C after 6 h for the Cu * /toluene sample. For the CO 2 to CH 3 OH reaction, a maximum conversion of 80% was obtained for the Cu * /pentane/NC-ZnO sample. In general, the Cu * /nanocrystalline (NC)-ZnO samples show a larger conversion of CO 2 to methanol at 450 °C compared with NC-ZnO and NC-ZnO/CuO.