Synergistic S-Scheme mechanism insights of g-C3N4 and rGO combined ZnO-Ag heterostructure nanocomposite for efficient photocatalytic and anticancer activities

The g-C3N4/rGO/ZnO-Ag (GCRZA) composite photocatalyst (PC) prepared by the facile hydrothermal method was effectively studied. The structural, morphological and optical, properties of as-synthesized materials were characterized by various characterization techniques. Photocatalytic activity of the as-prepared composite was examined using rhodamine B and methylene blue mixed (RhB+MB) aqueous dye under UV–visible light irradiation for 100 min. The GCRZA composite displayed a better photocatalytic performance against MB dye (90.04%) and RhB dye (83.45%) degradation performance. Moreover, the GCRZA composite PCs exhibited higher photocatalytic activity than pristine g-C3N4. The ultimate photocatalytic property was attained by implementating of g-C3N4/rGO in ZnO-Ag heterostructure, which could effectively decrease the optical bandgap and high visible-light absorption ability with suppressed e−/h+ recombination rate. After the five consecutive photocatalytic recycles, the GCRZA composite PC showed good stability without structural changes. Furthermore, the IC50 values showed that GCRZA nanocomposite (NC) has a higher cytotoxicity effect than g-C3N4/ZnO-Ag, g-C3N4/rGO and g-C3N4 against both HeLa and MCF-7 cell lines. As a result, this combination of nanocomposite has proven to exhibit higher photocatalytic and anticancer activity. Eventually, it may prove to be an effective tool for eradicating dye pollution from wastewater, and a way to prevent cancer mediated diseases in the cosmetics and pharmaceutical industries.