Ultrathin TiO2(B) nanosheets-decorated hollow CoFeP cube as PMS activator for enhanced photocatalytic activity

A novel TiO2(B)/phosphidated CoFe Prussian blue analogs (CoFeP) photocatalyst with core–shell structure was synthesized by hydrothermal method for the activation of peroxymonosulfate (PMS) to degrade TC under solar light. TiO2(B), an ultrathin two-dimensional (2D) layered material, is widely used in photocatalysis. However, the low light absorption efficiency and slow electron mobility limit the application of TiO2(B) in photocatalysis. Here, TiO2(B) was in-situ grown on the surface of phosphidated CoFe Prussian blue analogs (CoFeP). The composites with a core–shell structure can activate peroxymonosulfate (PMS) to degrade tetracycline (TC) under solar light. The optimized TiO2(B)/CoFeP heterojunction achieves a TC degradation rate of 94 % within 5 min, due to that it effectively suppresses the recombination of photogenerated charges and improves light absorption ability. The phosphorization of CoFePBA (CoFe Prussian blue analogs) not only promoted the formation of hollow structures but improved the carrier mobility between TiO2(B) and CoFeP. At the same time, the rapid redox cycle of Fe and Co metal ions promoted the activation of PMS and the rapid degradation of TC. This work provides a new core–shell TiO2(B)/CoFeP heterojunction for sustainable water purification via PMS activation.