Energy band regulation and heterophase surface heterojunction in B-C-N-TiO2 catalysts for enhanced photocatalytic activity

B-C-N-TiO 2 catalysts with intermediate band gap and heterojunction were prepared by sol–gel method. The crystal structure, elemental composition, and absorbance performance were analyzed by XRD, XPS and UV–vis DRS. Due to the formation of the continuous intermediate band gap in the forbidden band, the optical absorption boundary of B-C-N-TiO 2 catalyst extends to 412 nm, which shows different red shift compared with that of TiO 2 (397 nm), N-TiO 2 (400 nm), B-TiO 2 (402 nm) and C-TiO 2 (403 nm).Meanwhile, the B-C-N-TiO 2 catalyst is a uniform spherical solid particle with exposed (101) and (211) planes. The degradation efficiency of B-C-N-TiO 2 catalyst to methylene blue(MB) was up to 97.82% after 3 h under visible light, which shows different degree of improvement compared with that of TiO 2 (34.8%), N-TiO 2 (79.09%), B-TiO 2 (87.82%) and C-TiO 2 (73.19%). B-C-N-TiO 2 has good stability, and there was still more than 95% degradation efficiency after three degradation cycles. It is also revealed that the incorporation of B-C-N element affects the crystal phase of the catalyst and promotes the generation of heterophase surface heterojunction between (101) and (211). It has certain guiding value for co-doping modification of three elements.