Synthesis and Photocatalytic Performance of a Prussian Blue–Zn₂SnO₄ Composite for Visible-Light Degradation of Methiyene Blue

In this study, a Prussian Blue–Zn₂SnO₄ (PB-Zn₂SnO₄) composite was successfully synthesized via a facile physical mixing-assisted deposition approach and evaluated as an efficient visible-light-driven photocatalyst for the degradation of methylene blue (MB). The structural and physicochemical properties of the synthesized materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area analysis, and UV–visible diffuse reflectance spectroscopy (UV–Vis DRS). XRD analysis confirmed the crystalline nature of the individual components and the formation of a heterostructured composite with nanocrystallite domains (<15 nm). BET analysis revealed that the composite exhibited a significantly enhanced surface area (74.9 m² g^-1) compared to pristine PB (62.3 m² g^-1) and Zn₂SnO₄ (28.7 m² g^-1), indicating improved porosity and dye adsorption capability. UV–Vis DRS analysis showed that the composite material had extended visible-light absorption due to synergistic optical effects. Photocatalytic tests under visible light demonstrated that the PB-Zn₂SnO₄ composite achieved up to 95% degradation of MB within 60 minutes. The enhanced performance is attributed to the efficient separation of photogenerated charge carriers across the heterojunction interface, as well as the increased surface reactivity of the composite. These results highlight the potential of the PB-Zn₂SnO₄ composite as a promising visible-light-active photocatalyst for environmental remediation applications.