fig5
Figure 5. Comparison of the XPS spectra. (A) Biding energy comparison of Ir4f between IrCl3·3H2O (bottom) and the Ir/POP-Phen (top); (B) Biding energy comparison of N 2p between POP-Phen (bottom) and the Ir/POP-Phen (top); (C and D) Ir4f and N 2p spectra of the Ir/POP-Phen-spent. XPS: X-ray photoelectron spectroscopy; Ir/POP-Phen: porous phenanthroline-based polymer-supported single-iridium-atom catalyst.
