Because the color of the ZnO sample is white, it is sure that the carbon signal found in the spectrum is derived
from the carbon conductive tape which is used to fix ZnO–Au powder on the sample stage of SEM. Besides, the optical
images exhibited in Fig. 8d reveal obvious color difference between ZnO nanobelts and ZnO–Au composite due to
localized surface plasmon resonance of noble metallic NPs, which also implies that Au NPs have been assembled on the
surface of the nanobelts.