Fabrication of heterojunction MnTiO₃–TiO₂-decorated carbon nanofibers via electrospinning as an effective multifunctional photocatalyst

In this paper, we successfully synthesized heterojunction manganese titanate/titanate nanoparticles (MnTiO₃–TiO₂ NPs)-decorated carbon nanofibers (CNFs) employing the electrospinning process. The morphology, crystallinity, and chemical composition of the MnTiO₃/TiO₂-decorated CNFs is characterized via SEM, FESEM, STEM, TEM EDX, and XRD techniques. The synthesized nanocomposite exhibits good performance for photodegradation of methylene blue (MB) dye and hydrolysis of ammonia–borane complex for hydrogen releasing experiment in a batch reactor under visible light. A mathematical model was developed to predict the photocatalytic activity of the produced nanocomposite with various parameters. The operational parameters include the effect of the initial concentration, catalyst dosage, light intensity, and reaction temperature, which are studied to validate the mathematical model. The reaction rate constant of MB photodegradation is found to be 0.0153 min⁻¹ for an initial MB concentration of 5 mg·L⁻¹ with a catalytic dosage of 200 mg·L⁻¹ at a reaction temperature of 25°C under a light intensity of 25 W·m⁻². Similarly, the H₂ generation employing TiO₂@CNFs and MnTiO₃/TiO₂@CNFs under visible light irradiation is observed to be 0.31 mol and 2.95 mol, respectively, corresponding to an exposure of 10 min. We also demonstrated that the yield of hydrogen employing MnTiO₃/TiO₂@CNFs under visible light increases to 2.95 mol compared with 1.51 mol in darkness. Finally, comparisons were made between the experimental and model-predicted values of the reaction rate constant and final concentrations. Theoretical and experimental data of photocatalytic activity are found to be in good agreement for MnTiO₃/TiO₂@CNFs.