Fig. 2: Structural and compositional analysis of TpBpy before and after H2O2 photosynthesis.

a Schematic of enol/keto and imine/amine group roles (E = enol, K = keto). b, c FT-IR spectral changes of TpBpy during H2O2 synthesis. d NMR spectra of TpBpy before and after H2O2 photosynthesis (spin sidebands marked with *). e, f N1s and O1s XPS spectra of TpBpy before and after H2O2 photosynthesis.