Fig. 1

Characterization of CMC. (a, b) TEM images of Cu2O and CMC. (c) Photographic images displaying the colors of Cu2O (yellow) and CMC (dark green) at the same concentration. (d-f) UV-visible absorption spectra, Zeta potential (n = 3), and hydrodynamic diameters of Cu2O and CMC (n = 3). (g, h) XRD spectra of Cu2O and CMC. (i-p) XPS spectra of Cu2O and CMC, including measurements of survey XPS, high-resolution C 1s, Cu 2p, and O 1s spectra