<p>This study presents the synthesis of a Bi₂S₃/BiVO₄ heterostructure using a hydrothermal method with ammonium metavanadate, bismuth nitrate, and thioacetamide, in the presence of hydrazine. To better understand the role of hydrazine, experiments were also conducted using other hydroxide control agents including nitric acid and hydrochloric acid. The simplicity and efficiency of this method make it highly effective in producing nanoparticles with desirable properties. The structural, morphological, and compositional characteristics of the photocatalyst were examined using XRD, DRS, FT-IR, EDS, and FESEM. The results showed that hydrazine significantly influences the formation of the Bi₂S₃/BiVO₄ heterostructure, enhancing its photocatalytic activity. In contrast, other reagents led to different crystalline phases in the resulting nanocomposites. Bi₂S₃/BiVO₄ heterojunction photocatalyst synthesized with hydrazine showed higher photocatalytic activity than other composites, such that it was able to desulfurize 91% of dibenzothiophene and 92% of diesel fuel under visible light irradiation for 30&#xa0;min. In the recyclability test of the synthesized Bi₂S₃/BiVO₄ photocatalyst, the desulfurization efficiency decreased from 92 to 86% (negligible efficiency loss) after four cycles, which is a favorable result of the stability of the photocatalyst.</p>