Synthesis of conducting bifunctional polyaniline@mn-TiO₂ nanocomposites for supercapacitor electrode and visible light driven photocatalysis

We report a polyaniline-wrapped, manganese-doped titanium oxide (PANi/Mn-TiO₂) nanoparticle composite for supercapacitor electrode and photocatalytic degradation. The PANi/Mn-TiO₂ nanoparticles were synthesized using a solvothermal process, followed by oxidative polymerization of aniline. The structural properties of studied materials were confirmed by XRD, FTIR, HRTEM, FESEM, and UV visible spectroscopy. The as-prepared PANi/Mn-TiO₂ nanoparticles revealed admirable electrochemical performance with a specific capacitance of 635.87 F g⁻¹ at a current density of 1 A g⁻¹ with a notable life cycle retention of 91% after 5000 charge/discharge cycles. Furthermore, the asymmetric cell with PANi/Mn-TiO₂ as a positive electrode exhibited energy density of 18.66 W h kg⁻¹ with excellent stability. Moreover, the PANi/Mn-TiO₂ had promising photocatalytic activity for methylene blue degradation. The improved performance of PANi/Mn-TiO₂ nanoparticles is attributed to the well-built synergetic effect of components that lead to significant reduction of band gap energy and charge transfer resistance, as revealed by UV visible spectroscopy and electrochemical impedance spectroscopy.