3. Results and discussion
The morphology and particle size of the prepared particles were analyzed with scanning and transmission electron microscopy as shown in Fig. 3. Nearly monodispersed spherical particles with a mean diameter of 41 nm and a standard deviation of 6.72 nm were obtained (Fig. 3a). From the results shown in this figure, it also confirm that present method can be used to prepare particles with porous surface structures.
To verify the porous structure of the particle, the prepared particles were also characterized using TEM. As shown in Fig. 3b, the TEM images indicate that the prepared particles contained pores that were approximately 5 nm in size, which were larger than that the pores observed in previously reported results [17]. The porous morphology of particles (as assessed by SEM) was similar to the TEM results. The high-resolution TEM confirmed the existence of pores both on the particle surface and inside the particle. Selfassembly structures were obtained in all prepared particles. In addition, after thermally removal of the organic templates, no particle swelling or shrinking was observed. This result confirmed that heat treatment is a reasonable method for removal of the organic templates, as it had no effect on particle morphology and size.
Fig. 4 shows the sorption properties of the prepared particles.
The calcined particle exhibited a characteristic type-IV curve,