Figure 1

High-resolution XPS spectra of the A-CQDs/W sample: (A) C 1s XPS spectra (B) W 4f XPS spectra, (C) N 1s XPS spectra and (D) O 1s XPS spectra.
High-resolution XPS spectra of the A-CQDs/W sample: (A) C 1s XPS spectra (B) W 4f XPS spectra, (C) N 1s XPS spectra and (D) O 1s XPS spectra.