Chloroplast inspired Z-scheme photocatalyst for efficient degradation of antibiotics: Synergistic effect of full-visible light response, multi-channel electron transport and enhanced molecular oxygen activation

Abstract

Inspired by natural photosynthesis, we mimic chloroplast and synthesize a novel Z-scheme heterojunction photocatalyst BiOBr/RGO/TCPP. After 60 min irradiation of visible light, the final removal efficiency of tetracycline (TC) by BiOBr/RGO/TCPP reached about 90% with little interference from the solution pH, natural organic matter (NOM), and coexisting inorganic ions. The BiOBr/RGO/TCPP have chloroplast-mimicking multifunctional components and layered interconnect heterostructure. The meso-tetra(4-carboxyphenyl)-porphyrin (TCPP) was highly dispersed in BiOBr, which functions as the chlorophyll to enhance efficient light absorption. The built-in electric field in the layered structure of BiOBr and the interconnecting RGO nanosheet form multi-channel electrons and energy transport chain, tuning the charge transfer between TCPP and BiOBr from type-II to Z-scheme model, enhancing the electron transfer from BiOBr to TCPP. The low LUMO position of TCPP boosts the generation of ·O2– with strong oxidative ability. In addition, the results of acute antibacterial properties and the ECOSAR program showed that the toxicity after photocatalytic degradation was significantly reduced. In conclusion, this concept of the chloroplast-mimicking model provides new insights into the design of high photo-absorbing heterojunction photocatalysts for the removal of antibiotics.