Design of a MWCNT integrated advanced ternary composite with dual functionality in energy storage and photo catalytic dye detoxification

Polluted water harms human health and the planet's wellbeing alike. Tackling the global energy crisis driven by rapid economic expansion and our reliance on power hungry gadgets demands innovative clean energy storage solutions. This study developed a ternary heterojunction photocatalyst based on g-C₃N₄/TiO₂/MWCNTs studied their structural, optical, and morphological properties, the produced materials were thoroughly evaluated via XRD, FTIR, BET, UV-Vis DRS, PL, SEM, TEM, Raman, and XPS studies. The photocatalytic activity of the g-C₃N₄/TiO₂/MWCNTs nanocomposite was evaluated via the degradation of rhodamine B dye under solar light with various parameters, and the results revealed that the g-C₃N₄/TiO₂/MWCNTs nanocomposite had 99% degradation efficiency with Z scheme mechanism and outperformed the pristine g-C₃N₄ sheet and TiO₂, with approximately 1.3 and 1.4 folds higher degradation rates, respectively. The photodegradation process was followed by pseudo first-order kinetics with a rate constant of 0.0922 min⁻¹, resulting in a 2.36 and 3.16 fold increase compared to pristine catalysts. The HR-MS and scavenger test results suggested that intermediates formed and that photoinduced radicals play important roles in the photodegradation process. Electrochemical impedance spectroscopy revealed improved electrical conductivity, and cyclic voltammetry investigations revealed an outstanding specific capacitance of 1860 F/g at 30 mV/s nearly six times greater than that of pristine g-C₃N₄ (348 F/g).The remarkable photocatalytic performance and good electrochemical properties of the g-C₃N₄/TiO₂/MWCNTs heterojunction highlight its promise as a multifunctional material for environmental purification and energy storage applications.