Comparative Synthesis of Cu and Cu₂O Nanoparticles from Different Copper Precursors in an Ionic Liquid or Propylene Carbonate

Abstract

Abstract Copper metal and copper(I) oxide (cuprite, cuprous oxide) nanoparticles (Cu‐NPs and Cu 2 O‐NPs) were prepared from different readily available copper salts by means of microwave irradiation in propylene carbonate (PC) or in the ionic liquid (IL) 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIm][BF 4 ]) without addition of extra reducing agents. The nanostructures were studied by high‐angle annular dark field‐scanning transmission electron microscopy, TEM, SEM, and powder XRD. Star‐shaped agglomerated Cu‐NPs with about 45 nm diameter were formed from Cu(BF 4 ) 2 in PC. Cu‐NPs with smaller size distributions of 3.1 ± 0.7 nm and 3.7 ± 1.4 nm were obtained when copper(II) bis[1‐(dimethylamino)propan‐2‐olate], Cu[OCH(Me)CH 2 NMe 2 ] 2 , was decomposed in PC and in [BMIm][BF 4 ]. Small Cu‐NPs were also obtained from copper(II) acetylacetonate in [BMIm][BF 4 ] with a diameter distribution of 3.3 ± 0.9 nm. Cubic Cu 2 O nanocubes (Cu 2 O‐NCs) of 43 ± 15 nm in size could be prepared by using Cu(OAc) 2 · H 2 O with [BMIm][BF 4 ]. The size of the Cu 2 O‐NCs increased on isolation from the neat IL by addition of acetonitrile, which gave NCs of 0.1–0.5 μm in size.