Interfacial Engineering and Photon-Activated Photocatalysis of SCG-Derived Carbon/g-C₃N₄/Fe₃O₄ Ternary Hetero structures for Methylene Blue Degradation

The development and synthesis of a ternary SCG/carbon/g-C3N4/Fe3O4 magnetic nanocomposite has been undertaken using a myriad of methods, such as thermal polymerization and co-precipitation of FeCl3·6H2O and FeCl2·4H2O, combined with carbonization of spent coffee grounds, and finally completion via simple magnetic stirring[42]. FTIR results confirm the presence of Fe-O stretching (588 cm-1), triazine rings (805 cm-1), C-N/C=N bands (g-C3N4) and O-H/C-O groups (SCG carbon). XRD analysis also showed crystalline Fe3O4, with sharp peaks measured at 2θ 33.44°, 35.96°, 54.39° and 62.82° respectively, with an average crystallite size of 62 nm, as well as a broad amorphous peak between 24-28°, attributed to the presence of carbon and g-C3N4. The zeta potential (-0.1 to - 0.6 mV) indicates a slightly negatively charged surface suitable for the adsorption of cationic dyes. DLS indicates the presence of a bimodal distribution, with a significant fraction found to be at approximately 367 nm (90.9%). EDS analysis demonstrated high purity of the sample being measured, with C (24.7%), N (29.4%), O (17.2%) and Fe (28.7%) all detected within the chemical composition.

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