A novel chemical reaction between P25 and γ-Bi₂O₃ in CaTiO₃ preparation constructing two new transfer channels of charge carriers to boost photocatalytic degradation activity

For the current design of heterojunction, only one new transfer channel of charge carriers was generated. In this paper, a novel chemical reaction between P25 and γ-Bi₂O₃ generated Bi₄Ti₃O₁₂ to construct two new transfer channels in the preparation process of CaTiO₃. The optimal sample CaTiO₃/Bi₄Ti₃O₁₂/γ-Bi₂O₃-12 could degrade 94 % of bisphenol A and 99 % of bisphenol AF, which was much higher than those of the pure phases and the two-phase junction samples. The photocatalytic efficiency of these two pollutants remained 94 % and 99 % in the five cycle tests to indicate that the above new channels were not destroyed after continuous utilization. The main active substances were hole, electron and superoxide radical O₂^–• in process of degradation. Different wastewater environments held a slight impact on photocatalytic efficiency to reveal a good applicability in real-world environments. After 90 min, the TOC and COD removal efficiencies of bisphenol A also attained 43 % and 44 % while those of bisphenol AF reached to 77 % and 83 %. The excellent photodegradation activity came from the formation of two new channels to accelerate the spatial separation of charge carriers. The colony numbers of Escherichia coli were 0.87 × 10^-6 CFU/mL and 0.88 × 10^-6 CFU/mL in the solution degraded by bisphenol A and bisphenol AF to show the non-toxicity of the final product. Thus two new transfer channels were obtained via P25 reacting with γ-Bi₂O₃ to enhance the catalyst activity, opening up a unique idea for heterojunction preparation.