Influenceof Reducing Atmosphere of Subcritical/SupercriticalMild Alcohols on the Synthesis of Copper Powder.

Copper powder with different sizewas synthesized using subcritical/supercriticalmild alcohols without additional reductant. The interaction influenceof the reducing atmosphere, including temperature, pressure, precursors,and alcohol types, was investigated. XRD and SEM were applied to analyzethe composition and morphology of products synthesized. Results showedthat the reducing atmosphere formed by critical conditions, precursors,and mild-alcohol types had a significant effect on the products. Thereducing atmosphere could be enhanced obviously with higher temperatureand pressure. CuO was easier to reduce than Cu(NO3)2and CuSO4under the same conditions. Comparedwith ethanol, methanol could form a stronger reducing atmosphere atthe same temperature and pressure. Supercritical methanol (250 °C,9 MPa) with CuO as a precursor could provide the optimal reducingatmosphere for the synthesis of copper powder. In addition, it wasproposed that mild alcohols should play an important role as cappingagents as well as reducing agents under subcritical/supercriticalconditions. [ABSTRACT FROM AUTHOR]