Fig. 4: Electronic characterizations of four COFs.
From: Post-synthetic modification of covalent organic frameworks for CO2 electroreduction
The XPS spectra of a Co 2p and b N 1s for CoTAPP-PATA-COF, N+-COF, NH-COF and N+-NH-COF. c The UV-vis absorption (insert: Tauc plots) and d the energy gap (HOMO and LUMO) for CoTAPP-PATA-COF (black), N+-COF (green), NH-COF (blue) and N+-NH-COF (red).
