Solid-state fabrication of BiOBr/Bi24O31Br10 lattice heterojunction for photocatalytic reduction of CO2 and degradation of RhB

The contact degree of heterojunction plays a crucial role to the separating efficiency of photo-generated carriers. Herein, a nano-sheet like BiOBr/Bi24O31Br10 lattice heterojunction is firstly prepared from a simple solid-state chemical reaction. The phase transformation from BiOBr to BiOBr/Bi24O31Br10, then to pure Bi24O31Br10 can be realized simply by the thermal annealing process. Benefiting from the enhanced photoinduced carrier separation efficiency of the formed lattice heterojunction, the BiOBr/Bi24O31Br10 composite exhibites excellent photocatalytic capability to reduce CO2 to CO, which has a stable yield of CO (29.19 μmol g−1) after 5 h of continuous catalytic reaction, the reaction rate constants are 4.2 and 3.5 times higher than that of pure Bi24O31Br10 and BiOBr, respectively. Meanwhile, the heterostructures present super photocatalytic degradation ability for rhodamine B (RhB) under visible light. The mechanism of the photocatalytic reduction and oxidation process is systematically investigated and proposed. This work provides an effective strategy to design staggered heterojunction photocatalyst by a solvent-free method and reveals the mechanism of lattice heterostructure for boosting photocatalytic performance.Graphical abstract