## 3 Results and Discussion  
### Morphology  
Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to analyze the morphology and elemental composition of the composite fibers. Figures 2-4 show the SEM images with different magnifications of the \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)/C, TiO\({}_{2}\)/C, and \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\)/C composite nanofibers. For the \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)/C composite fibers, it was appreciated that after calcination, these fibers possessed a rough textured surface while maintaining a solid cross-section. Upon carbonization, the TiO\({}_{2}\)/C fibers showed a smooth solid fiber morphology, as seen in the SEM images. The cross section of the Fe\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\)/C composite fibers demonstrated a degree of porosity within the fibers, in contrast to the Fe\({}_{2}\)O\({}_{3}\)/C and TiO\({}_{2}\)/C composite fibers shown in Figures 2 and 3.  
The crystal structure and morphology of the \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\)/C composite fibers were further analyzed using TEM and HRTEM, as shown in Figure 5A,B. The TEM image of the \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\)/C carbon composite fibers shows the \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\) nanoparticles being deposited on the surface of carbon fibers. Figure 5B shows a typical high-resolution TEM (HRTEM) image taken from the \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\) nanoparticles on carbon fibers. The most common spacing in the TEM images is in the 0.34-0.35 nm range, which corresponds to the (101) anatase spacing. Figure 6B also shows crystalline lattice spacings of 0.24 nm and 0.27, which correspond to the 004 and 104 crystalline planes of anatase and Fe\({}_{2}\)O\({}_{3}\), respectively. The particles were heavily agglomerated in all images but were estimated to have diameters of 3-5 nm. The 3.25 A fringes on the larger particles do match the (110) spacing for anatase.  
Figure 4: SEM images of the ternary \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\)/C composite fibers after heat treatment. Magnification: (**A**) 3000 and (**B**) 30,000.  
Figure 5: TEM images of Fe\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\)/C composite fibers showing (**A**) aggregates of crystalline material on the surface of the fiber and (**B**) polycrystalline structure of one of these aggregates.  
The energy dispersive X-ray spectrometry (EDS) mapping images and HAADF of \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\)/C composite fibers (Figure 6) suggest that the \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\) and TiO\({}_{2}\) nanoparticles and CFs were well-distributed in the as-prepared materials. The TEM elemental maps of the \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\)/C composite fibers confirm that the primary constituent elements are C, Ti, O, and Fe. The phase mapping of the \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)/TiO\({}_{2}\)/C composite-fiber spectra in Figure 6 suggests that the key elements of Ti, Fe, and C are uniformly distributed throughout the composite fibers. Note that the Cu peak in the EDS spectrum (Figure 6B) arises from the sample support TEM grid. Especially in the case of thick samples (200-400 m), such as the composite fibers in this work, a large portion of the electron intensity is scattered to the sides at high angles.