Fig. 2: Structural characterizations of MHP-P5Q.

a Solid-state 13C CP-MAS NMR spectrum. The asterisk denotes spinning sidebands. b N 1s XPS spectrum. c FT-IR spectra of MHP and MHP-P5Q. d, e FE-SEM images at different scales. f HR-TEM image.

a Solid-state 13C CP-MAS NMR spectrum. The asterisk denotes spinning sidebands. b N 1s XPS spectrum. c FT-IR spectra of MHP and MHP-P5Q. d, e FE-SEM images at different scales. f HR-TEM image.