2.1.3. Scanning Electron Microscopy (SEM)

The SEM images of hectorite, TH-1, TH-2, TH-3, TH-4, and TH-5 are shown in Figure 3. Figure 3a shows the typical structure of hectorite, which is a nanoscale layered structure and forms blocky particles with various sizes, rough surfaces, and different thicknesses [15]. SEM images of the five TiO2/hectorite with different initial material ratios are given in Figure 3b–f. After the introduction of TiO2, the structure of TiO2/hectorite is different from that of hectorite. The particle size of hectorite pillared by TiO2 is significantly reduced, showing a looser structure and disordered accumulation of flake structure, which can increase the specific surface area, enhance the adsorption ability, and improve the photocatalytic effect [10].

The lamellar structure of TiO2/hectorite also shows that the ion leaching degree in the structure of hectorite is small and the skeleton is damaged to some degree, which is consistent with the XRD analysis results. The SEM images of TH-4 and TH-5 show a higher degree of agglomeration and lower nucleation of agglomerates in comparison with the TH-2 sample. In particular, the pattern of TH-5 gives an increase in irregular shape compared with other samples, which may be due to the excessive content of lithium ions inhibiting the entry of titanium ions into the layers of hectorite and agglomerating on the surface.
