In Situ Synthesis of Bi₂MoO₆/Bi₂SiO₅ Heterojunction for Efficient Degrading of Persistent Pollutants

Photocatalytic degradation is an environmentally friendly way to eliminate environmental pollution. Exploring a photocatalyst with high efficiency is essential. In the present study, we fabricated a Bi₂MoO₆/Bi₂SiO₅ heterojunction (BMOS) with intimate interfaces via a facile in situ synthesis method. The BMOS had much better photocatalytic performance than pure Bi₂MoO₆ and Bi₂SiO₅. The sample of BMOS-3 (3:1 molar ratio of Mo:Si) had the highest removal efficiency by the degradation of Rhodamine B (RhB) up to 75% and tetracycline (TC) up to 62% within 180 min. The increase in photocatalytic activity can be attributed to constructing high-energy electron orbitals in Bi₂MoO₆ to form a type II heterojunction, which increases the separation efficiencies of photogenerated carriers and transfer between the interface of Bi₂MoO₆ and Bi₂SiO₅. Moreover, electron spin resonance analysis and trapping experiments showed that the main active species were h⁺ and •O₂^- during photodegradation. BMOS-3 maintained a stable degradation capacity of 65% (RhB) and 49% (TC) after three stability experiments. This work offers a rational strategy to build Bi-based type II heterojunctions for the efficient photodegradation of persistent pollutants.