Phase‐manipulable synthesis of Cu‐based nanomaterials using ionic liquid 1‐butyl‐3‐methyl‐imidazole tetrafluoroborate

Abstract

AbstractUsing the ionic liquid (IL), 1‐butyl‐3‐methyl‐imidazole tetrafluoroborate, and the precursor Cu7Cl4(OH)10·H2O, series of phase‐manipulable Cu‐based nanomaterials were synthesized by hydrothermal and microwave assisted routes, respectively. The structural characters of the as‐prepared CuO, CuO/Cu2O composites and pure Cu nanoparticles were investigated by XRD, SEM, TEM and HRTEM, and their surface photovoltaic properties were studied by surface photovoltage spectra. Via hydrothermal route Cu2+ ions were found to be reduced gradually into Cu+ and subsequently Cu0 with increasing the IL, and various phase ratio of CuO, Cu2O and Cu composite nanosheets and pure Cu nanoparticles were obtained. This implies that the IL could function as both a reductant in the oxygen‐starved condition and a template for the nanosheet products. The 1H‐NMR result of the IL supports it being a reductant. In microwave assisted route, however, only monoclinic single crystalline CuO nanosheets were obtained, which indicates the IL being a template only in oxygen‐rich condition. Therefore, the crystal phase, composition and morphology of the Cu‐based products could be controlled by simply adjusting the quantity of the IL and oxygen in solution routes. The molecular structure of the IL after oxidation reactions was investigated by 1H‐NMR and a possible reaction mechanism was proposed. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)