*2.5. GO Characterization*

To investigate the phototransformation of GO, the changes in GO in the photoreaction system were characterized by UV–vis spectrophotometry from 200 nm to 600 nm. Additionally, the Raman spectra were measured at 1000 cm<sup>−</sup><sup>1</sup> to 2000 cm<sup>−</sup><sup>1</sup> with 532 nm excitation with a Raman spectrometer (Renishaw inVia Reflex, New Mills, UK) before and after UV illumination.
