Co-implanting of TiO2 and liquid-phase-delaminated g-C3N4 on multi-functional graphene nanobridges for enhancing photocatalytic degradation of acetaminophen

[Display omitted] •The indirect Z-type TGCN hybrid was synthesized successfully.•The ultrathin g-C3N4 nanosheets obtained through an acid-treatment-assisted process.•TGCN/SSL process showed an excellent efficiency into ACM and TOC removal.•The plausible mechanism of charge separation and transportation was discussed. Herein, an efficient all-solid-state Z-type photocatalyst, TiO2/graphene/g-C3N4 (TGCN), was fabricated, characterized and utilized toward acetaminophen (ACM) degradation under a simulated solar light (SSL). The acid-treatment-assisted exfoliation process was used to break Van-der-Waals bonds between the bulk g-C3N4 layers and yield of ultrathin g-C3N4 nanosheets was fully explained. Also, the importance of using HCl and water in the process was examined. Structural, morphological and surface features of samples were thoroughly determined using XRD, Raman, TGA, FTIR, EDX, DRS, TEM, HRTEM, FESEM, BET, PL, EIS and photocurrent analyses. By considering different locations of graphene nanosheets in the TGCN, different charge transfer mechanisms were purposed and investigated employing Coulomb’s law and trapping experiments. Constructing the efficient Z-type photocatalyst by introduction of graphene as shuttle electron mediator to TiO2 and g-C3N4 nanocomposite significantly enhanced the degradation performance and photo-activity. The adsorption edge of the TGCN nanocomposite was extended to the visible·light region by g-C3N4 nanosheets benefiting a more favorable band gap position. The characterization results clarified that graphene facilitates photo-induced electron transportation and separation as well as improving the specific surface area and promoting the ACM adsorption capacity. Then, the most possible indirect Z-type charge separation mechanism for TGCN/SSL system was successfully confirmed by findings. Benefiting from the excellent synergetic effect of the catalyst individual systems, the ACM (50 mg/L) could reach up to complete degradation under SSL irradiation with the 0.6 g/L of TGCN (60:10:30) at pH = 9.0 within 120 min reaction. In the end, a tentative pathway for ACM decomposition was suggested.