Preparation And Electrochemical Performance Of TiO₂ Nanorod/Graphene Oxide Composites

nanorod/graphene oxide (TiO2 nanorod/GO) composites with different weight ratios were successfully prepared by self-assembly of GO and ready-made TiO2 nanorods under room temperature conditions. TiO2 nanorods were synthesized via the hydrothermal method, and GO was obtained via a modified Hummers method. X-ray diffraction, atomic force microscopy, and high-resolution transmission electron microscopy indicated that rutile TiO2 nanorods were loaded on the GO nanosheet without obvious aggregation, a redshift of about 15 nm in UV-vis DRS was observed in the absorption edge of TGO2 compared with that of pristine TiO2 and P25, which is attributable to narrowing of the band gap by chemical bonding between TiO2 and GO, that is, the formation of Ti-O-C bonds, similar to the case of carbon-doped TiO2 composites. Raman spectroscopy showed that the calculated ID:IG of GO was 0.844 and that the calculated ID:IG values of a series of TiO2 nanorod/GO nanocomposites with different GO contents of 2.04 wt.%,4.00 wt.%,7.69 wt.%,11.1 wt.%, and 14.3 wt.% were 0.884,0.647,0.710,0.831, and 0.874, respectively. The calculated ID:IG values of nearly all of the prepared TiO2 nanorod/GO nanocomposites were lower than that of GO, which indicates a lower density of defects and higher crystallinity in TiO2 nanorod/GO composites. The graphitization degree increased significantly because of distortion of the GO layer by titanium atoms, and the conductivity of the TiO2 nanorod/GO composites was better than that of TiO2. The electrochemical performance of the TiO2 nanorod/GO composites was confirmed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 1 mol L-1 Na2SO4 aqueous electrolyte. Results showed that TiO2 nanorod/GO composites with 4.00 wt.%GO have excellent electrochemical performance. The maximum specific capacitance (Cs) of this composite electrode was 100 F g-1 at 5 mV s-1 scan rate. The TiO2 nanorod/GO composites also exhibited good electrochemical stability with a capacitance degradation of less than 20% over 3000 cycles. The electrochemical performance of the as-prepared nanocomposites could be enhanced by increasing chemical interactions between TiO2 and GO.