TiO2/CNT/GO heterostructure nanocomposite was synthesized by solvothermal method for the removal or degradation of methylene blue (MB). The physical and chemical characteristics were assessed by various characterization techniques such as scanning electron microscopy (SEM) confirmed the external and internal morphology of the heterostructure materials with irregular shapes. Transmission electron microscopy (TEM) showed that the internal structure was preserved after incorporating CNTs and GO into TiO2, and the average particle size distribution was determined using an SEM histogram with an average particle size of 85.5 nm. Energy dispersive X-ray spectroscopy (EDS) was performed to evaluate the elemental mapping of heterojunction confirm the presence of C, O, and Ti. X-ray diffraction (XRD) revealed a crystalline nature and the size of as synthesized material was calculated as 17.08 nm. UV–vis spectroscopy (UV–vis) was conducted to observe the optical behavior and light scattering phenomena of heterostructure materials. Various factors, such as different doses of heterostructure (0.1, 0.2, and 0.3 g), dye concentration (10, 20, and 30 ppm), irradiation time (0, 30, 60, 90, and 120 min), were carried out at 25 °C. The TiO2/ CNT/GO heterostructure induced 91% methylene blue (MB) degradation in 120 min with superior cycling stability after regeneration for four cycles. The optimal reaction conditions were adopted to obtain the highest degradation rate using 0.2 g of the heterostructure, 30 ppm MB concentration, 120 min of light irradiation, and 25 °C reaction temperature. The TiO2/ CNT/GO photocatalyst exhibited enhanced kinetic performance, catalytic stability, structural reliability, and reactivity for 91% degradation efficiency of MB.

Structural and photocatalytic properties of TiO2CNTGO heterojunction materials towards the enhanced degradation of methylene blue dye
    Abstract
        Graphical Abstract
    1 Introduction
    2 Material and methods
        2.1 Reagents and chemicals
        2.2 Synthesis of titanium dioxide
        2.3 Synthesis of graphene oxide
        2.4 Synthesis of TiO2CNTGO nanocomposites
        2.5 Characterization of the TiO2CNTGO heterostructure nanocomposites
        2.6 Dye degradation performance and photocatalytic mechanism
    3 Results and discussion
        3.1 FTIR, XRD, SEM, TEM, and UV–visible analyses of TiO2CNTGO nanocomposites
        3.2 Photocatalytic degradation of MB
        3.3 Cycling stability and regeneration of nanocomposites
    4 Conclusion
    Acknowledgements 
    References

• Parveen Akhter(Department of Chemistry, The University of Lahore, 1‑Km Defence Road, Lahore, Pakistan)
• Aimon Saleem(Department of Chemistry, The University of Lahore, 1‑Km Defence Road, Lahore, Pakistan)
• Ume‑Laila(Department of Chemistry, The University of Lahore, 1‑Km Defence Road, Lahore, Pakistan)
• Sundus Umer(Department of Chemistry, School of Science, Tianjin Key Laboratory of Molecular Optoelectronic Science, Tianjin University, Tianjin 300072, China)
• Murid Hussain(Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Lahore, Pakistan)
• Young‑Kwon Park(School of Environmental Engineering, University of Seoul, Seoul 02504, Republic of Korea)