Hydrothermal synthesis of rGO-TiO 2 nanocomposites for electrochemical performance

Hydrothermally reduced chemical method synthesis of rGO-TiO 2 nanocomposites (NCs) with varied concentrations of graphene oxide (GO) from 1 to 5 wt% was investigated for its morphological, structural, chemical bonding, structural defects, optical and electrochemical properties. Formation of rGO-TiO 2 NCs was confirmed from SEM and EDX analysis where the average particle size of TiO 2 nanoparticles dispersed over reduced graphene oxide (rGO) sheets increased from 46.2 to 71.2 nm. The diffraction peaks study from XRD reveals the TiO 2 phase in the anatase structure which is well supported by Raman results presenting the vibrational modes of Eg (1), Bg (1), A1g+B1g (2), and Eg (2) located at 146.1, 392.1, 513.2, and 638.1 cm −1 . The average crystallite size of rGO-TiO 2 NCs varied from 37.6 to 39.8 nm and lattice strain decreased from 0.0014 to 0.00135. The presence of the combination of Ti–O–Ti and Ti–O–C vibrational signatures indicates the effective interaction between Ti and C and the chemical bond formation between TiO 2 and rGO which is justified by X-ray photoelectron spectroscopy. Electrochemical measurements showed that the specific capacitance of rGO-TiO 2 NCs varied from 204.7 to 276.4 F g −1 at a 5 mV s −1 scan rate with the maximum specific capacitance obtained for 5% rGO-TiO 2 NC. The lowest charge transfer resistance was recorded for 5% rGO-TiO 2 NC (63.86 Ω) which is consistent with the maximum specific capacitance achieved. Moreover, corrosion studies reveal that corrosion potential becomes more positive with more rGO content obtaining a maximum of 0.297 V in 5% rGO-TiO 2 NC. Graphical Abstract