“…These fitted peaks at binding energies of 289.2, 286.4, 285.6, and 284.8 eV belong to OC–OH, CO, C–C and CC, respectively. 36 The Ce 3d spectrum (Fig. 2c) can be divided into eight peaks; the two peaks at BEs of 884.9 and 903.3 eV are ascribed to Ce 3+ , and the other six at 882.8, 889.1, 898.9, 901.4, 908.2, and 917.3 eV can be indexed to Ce 4+ .…”