Fig. 1 shows the X-ray diffraction (XRD) patterns of the as-synthesized
Bi3O2S3 nanoparticles. Except for the small impurity peaks
belonging to Bi28O32(SO4)10, the diffraction peaks observed on the
final powder product in Fig. 1(a) can be indexed to the orthorhombic
(I4/mmm tetragonal) phase for Bi3O2S3 with the cell constants
a = 3.961 Å and c = 41.316 Å. The intensities and positions of the
peaks are in good agreement with the values reported in the literature
[21]. Similarity, the diffraction peaks observed for the final
bulk product in Fig. 1(b) include the small impurity peaks identified
to Bi28O32(SO4)10. However, the XRD patterns from both the
powder and bulk samples show that the final products are absent
of Bi and Bi2OS2 in the Bi–O–S compound.