Multifunctional NiTiO3-decorated-rGO nanostructure for energy storage, electro- and photocatalytic applications

Herein, we report a synthesis of nanostructured multifunctional material: flakes of reduced graphene oxide decorated with NiTiO3 particles (NiTiO3/rGO). The structural and morphological features of the NiTiO3/rGO composite were investigated via X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), nitrogen adsorption/desorption analysis, Raman, infrared and UV–Vis spectroscopy techniques. The electrochemical performance was scrutinized through cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge measurements (GCD). The NiTiO3/rGO composite demonstrates an outstanding specific capacitance of 551 F g−1 (at 10 mV s−1) and an excellent capacitance retention (121 %). Its specific surface area (53 m2 g−1) increased by 100 % with respect to the pristine NiTiO3. The junction of NiTiO3 with rGO endowed the titanate with the mesoporous structure. NiTiO3/rGO presents supercapacitor behavior and has an attractive power characteristic with power density of 9718 W kg−1 (at 20 A g−1). The charge transfer resistance for NiTiO3/rGO, 56 Ω, is 2-fold smaller than for the bare NiTiO3. The composite behaved as electrocatalyst; it enhanced sensitivity of dopamine electrochemical detection. Biosensor showed linearity in the range 1–60 μM and limit of detection of 2.84 μM. NiTiO3/rGO also acted as visible-light harvesting photocatalyst and facilitated degradation of pharmaceutical pollutant, i.e. nizatidine. Photodegradation efficiency reached 35 % and 85 % with NiTiO3 and NiTiO3/rGO, respectively.