S-scheme Bi₁₂TiO₂₀/Bi₄Ti₃O₁₂ heterojunction immobilized on 3D-printed support as a monolithic photocatalyst for NO removal

Photocatalysis is recognized as one of the most promising techniques for environment purification. However, the inconvenient recovery of powder photocatalysts significantly impeded their practical applications. Immobilization of the photocatalysts on supports to form monolithic photocatalysts is an effective method to solve this problem. Herein, a monolithic photocatalyst Bi₁₂TiO₂₀/Bi₄Ti₃O₁₂/SiOC is fabricated by growing optimal Bi₁₂TiO₂₀/Bi₄Ti₃O₁₂ S-scheme heterojunction onto 3D-printed porous SiOC support. On one side, S-scheme heterojunction facilitates the separation of photoinduced electrons and holes while retaining their strong redox ability. On the other side, the porous structure favors mass transport and improves light harvesting by reflecting the light several times. Under simulated solar light irradiation, the NO removal efficiency of the monolithic photocatalyst Bi₁₂TiO₂₀/Bi₄Ti₃O₁₂/SiOC is 16.4 %. Furthermore, the composite has good stability and reusability, suggesting its great potential in practical application. The possible photocatalytic mechanism is proposed according to systematic experiments and density functional theory (DFT). This work provides a rational reference for constructing efficient photocatalysts for environmental purification.