Figure 4.

Photocatalytic activity of the Cu₂ZnSnS₄ nanoparticle toward the photodegradation of methylene blue (MB). (a) Time-dependent UV-vis absorbance spectra of the MB solution using the prepared Cu₂ZnSnS₄ nanoparticle as a photocatalyst. (b) Curves of the degradation rate of the MB dye with the prepared Cu₂ZnSnS₄ nanoparticle (C₀ is the initial concentration of MB; C is the reaction concentration of MB at time t). The inset shows the ln(C₀/C) versus time curve of the photodegradation of MB. (c) Time-dependent UV-vis absorbance spectra of the MB solution using the prepared Cu₂ZnSnS₄ nanoparticle and 0.1 mL H₂O₂ as photocatalysts. (d) Curves of the degradation rate of the MB dye with the prepared Cu₂ZnSnS₄ nanoparticle and 0.1 mL H₂O₂ as photocatalysts. The inset presents the ln(C₀/C) versus time curve of the photodegradation of MB.