Fig. 1
a Scheme illustration of the synthesis of CuO/C; b SEM images of CuO/C-350oC, CuO/C-400 °C and CuO/C-450 °C, the inset is the particle size statistics; c TEM, d HR-TEM and e Cu, O, C element mapping of CuO/C-400 °C; f XRD patterns of CuO/C-350 °C, CuO/C-400 °C, CuO/C-450 °C and the standard PDF of CuO; g XRD patterns for the 2Ɵ from 30˚ to 40˚; h EPR spectra of CuO/C-350 °C, CuO/C-400 °C and CuO/C-450 °C