Abstract <p>The presence of organic pollutants, such as rhodamine B (RhB), oxytetracycline (OTC), in aquatic and terrestrial environments poses a significant environmental challenge. This study introduces a new Type-II heterojunction photocatalyst, BiOBr modified with Bi₄Ti₃O₁₂ (Bi₄Ti₃O₁₂/BiOBr). A systematic investigation of the synthesis methods revealed that the composite photocatalyst produced via the molten salt method exhibited the highest degradation efficiency. Interestingly, maintaining a mass ratio of Bi₄Ti₃O₁₂ to BiOBr below 10% results in the Bi₄Ti₃O₁₂/BiOBr composite significantly outperforming the individual components, Bi₄Ti₃O₁₂ and BiOBr, in terms of photocatalytic performance. The Bi₄Ti₃O₁₂/BiOBr heterojunction effectively degrades various pollutants, including RhB and OTC, under visible-light irradiation, achieving an impressive degradation rate. Specifically, the photocatalytic degradation rate of RhB was 99.8% after 60&#xa0;min of irradiation at 298&#xa0;K and 101&#xa0;kPa. A mechanistic analysis of RhB degradation using the Bi₄Ti₃O₁₂/BiOBr photocatalyst identified superoxide radicals (·O₂⁻) and holes (<i>h</i>⁺) as the primary active species responsible for efficiently degrading pollutants. These results highlight the effectiveness of heterojunction construction in improving photocatalytic performance.</p> Graphical abstract <p></p> <p>The 0.04Bi₄Ti₃O₁₂/BiOBr catalyst demonstrates excellent photocatalytic degradation efficiency against Rhodamine B (RhB), achieving 99.8% degradation within 60 minutes under visible-light irradiation. This analysis identified superoxide radicals (·O₂⁻) and holes (<i>h</i>⁺) as the primary active species responsible for the efficient degradation of pollutants.</p>