High spatially resolved morphological, structural and spectroscopical studies on copper oxide nanocrystals

摘要

Copper oxide nanocrystals decorated on multi-wall carbon nanotubes have been prepared. Comprehensive morphological, structural and spectroscopical studies have been carried out on the nanometre/atomic scale by the combination of high-resolution transmission electron microscopy and electron energy-loss near-edge structure in electron energy-loss spectroscopy, which has a high spatially resolved capacity advantage over the normally used analytical techniques such as x-ray powder diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). The result reveals that highly crystalline cubic Cu2O nanocrystals with highly uniform dispersion, homogeneous size of about 5.3 nm and nearly spherical morphology are synthesized as the predominant phase, while rare individual monoclinic CuO nanocrystals with irregular shape are still present as the minor phase. The analysis based on the survey result and the structural symmetry difference between Cu2O and CuO demonstrates that XRD underestimates the presence of the CuO phase with much lower structural symmetry while XPS overestimates the proportion of CuO phase.