Study of enhanced photocatalytic performance mechanisms towards a new binary-Bi heterojunction with spontaneously formed interfacial defects

The directional design of interfacial defects is a promising way to promote charge separation but simultaneously a great challenge due to their random formation in heterojunction. Herein, an alternative Bi₁₂O₁₇Cl₂/Bi₂WO₆ heterojunction with interfacial defects formed spontaneously is prepared by controlling the growth of Bi₂WO₆ on the edges of Bi₁₂O₁₇Cl₂ nanobelts via ion exchange process. These interfacial defects can efficiently increase the carrier density and serve as charge separation centers to extend the lifetime of carriers and activate O₂ to ^[rad]O₂⁻ and further to ^[rad]OH. The zigzag interfaces and irregular edges facilitate the interaction between active sites and reactants. The heterojunction morphology and the interfacial defect concentration can be controlled by tuning the solvothermal time. Consequently, the optimal Bi₁₂O₁₇Cl₂/Bi₂WO₆ heterojunction exhibits significantly enhanced visible light photocatalytic performance toward the degradation of phenols, antibiotics and dyes as compared to that of mono-Bi Bi₁₂O₁₇Cl₂ and Bi₂WO₆ photocatalyst.