Fig. 3 has TEM images of the graphene oxide before the reduction.
Fig. 3(a) shows the lateral size of graphene oxide flakes,which revealed
that the graphene oxide's lateral size was more than 2 μm. Fig. 3(b) is
the magnified TEM image of graphene oxide and the layers are clearly
seen at the edge of the GO flakes: mostly 3 layers. Fig. 4 is an SEM
image of the cross-section of the RGO–TiO2 composite film displaying
a film thickness of about 14.5 μm. Fig. 5 is the SEM image of an enlarged
view of the top and a cross-section of the RGO–TiO2 photoelectrode
film, revealing a good mix between the RGO (flakes) and the TiO2 nanoparticles
(round particles). With an increase in amount of RGO in the
RGO–TiO2 nanocomposite, the stock of graphene flakes becomes more
apparent, as observed fromthe SEMimage in Fig. 6. The graphene flakes
may still not be completely covered by TiO2 nanoparticles even when
the amount of RGO goes beyond 1 wt.%.