Abstract <p>Using SnSO₄ and NaOH powder as reactants, we efficiently synthesized Sn₃(OH)₂OSO₄ photocatalysts via a precipitation reaction. Subsequently, by adjusting the heat treatment temperature, a series of samples were prepared to optimize their photocatalytic performance. The results indicate that the as-synthesized Sn₃(OH)₂OSO₄ material typically exhibits an ellipsoidal flower-like structure with particle sizes ranging from 5 to 15 µm. During the heat treatment of the Sn₃(OH)₂OSO₄ samples, it was observed that as the temperature increased, the Sn₃(OH)₂OSO₄ gradually decomposed, forming a composite of Sn₂OSO₄ and SnO. ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) revealed that compared to the untreated Sn₃(OH)₂OSO₄ sample, the synthesized samples demonstrated superior light absorption in both the partial ultraviolet range (310–400 nm) and the visible light region. Moreover, as the heat treatment temperature increased, the light absorption capacity of the samples gradually improved, while their bandgap values correspondingly decreased. Photocatalytic degradation experiments further confirmed that appropriately increasing the heat treatment temperature enhanced the samples’ degradation efficiency. Under ultraviolet light, visible light, and simulated sunlight irradiation, the best-performing sample (heat-treated at 350°C) was able to completely or nearly completely degrade methyl orange within 45, 60, and 30 min, respectively.</p>