“…The core energy spectrum of C 1s (Figure E) can be decomposed into four different peaks, corresponding to CO/CN (284.83 eV), CN (286.28 eV), and CO (288.33 eV) bonds. , The N 1s core-level spectrum in Figure F exhibited two peaks at 399.83 and 401.78 eV, which are attributed to the two components of CNC and NH, respectively. The O 1s core-level spectrum can be decomposed into CO (531.48 eV), −OH (533.03 eV), and −COOH (535.38 eV) bonds (Figure G). The Cr 2p core-level spectrum (Figure H) of Cr 2 O 3 NPs showed that there were three different states of chromium in Cr 2 O 3 NPs, including the Cr metallic bond (574.28 eV), , CrO 3 (589.28 eV), , and Cr 2 O 3 (576.38, 577.08, 579.83, 584.38, and 586.73 eV). − According to the Cr 2p signal, the ratios of Cr 2 O 3 , CrO 3 , and metallic Cr in our prepared nanoparticles were calculated to be 90.19, 5.41, and 4.40%, respectively.…”