**3.5 XPS analysis**

To determine the chemical composition of the CDAW and TiO2-MMC XPS analysis was performed. The surveys scan of CDAW in (**Figure 6**) illustrated that its oxygen content is around 17.4%, suggesting the containing of abundant surface oxygenic functional groups. In the C 1 s XPS spectra of CDAW (**Figure 6**), the peaks at 284.8, 286.7, and 288.9 eV are ascribed to the sp2 hybridized (C–C), alcoholic (C–OH) and carbonyl (C=O) carbon atoms, respectively.

The XPS survey scans of TiO2-MMC (**Figure 6**) show the typical spectra of TiO2-MMC (P25), and the more intense feature peak of C1s in TiO2-MMC was attributed to the layer of the hybrid. Concerning the C1s XPS spectra of TiO2-MMC, aside from the above listed characteristic peaks, it was noticed that an additional peak emerges at the binding energy of 283.5 eV, which is higher than that of titanium carbides (Ti4+ –C) and should be assigned to the carbon bonded with oxygen-deficient titanium ion (Ti3+ –C) revealing the distinctive chemically bonded carbon/TiO2-MMC. Besides, the atomic ratios of O: C for PAMC and TiO2-MMC are 0.21 and 0.17, respectively, suggesting the decreased oxygen content of coated PAMC TiO2-MMC [21–25].
