Tailoring the three-phase microenvironment surface to induce carbon nitride oxide generating center dot O-2(-) with 100% selectivity for ultrafast photodegradation tetracycline under visible light

The reactive oxygen species (ROS) contribute to photodegrading tetracycline (TC), which determines the overall efficiency of photocatalysts. Superoxide radical (center dot O-2(-)) is one of the excellent ROS for photodegrading TC by carbon nitride. However, achieving hierarchical carbon nitride with efficient, stabile, and selective production of center dot O-2(-) via O-2 photoreduction is a great challenge. Herein, a carbon nitride oxide nest (CNON6) with carbon/ni-trogen vacancies (C-v, N-v) and oxygen substitution (O-s) was prepared via tailoring surface microenvironment. The CNON6 can photodegrade 82% of TC within 2 min under visible light, and the pseudo-first-order kinetic constant is 1.22 min(-1), 24-fold higher than that of CN. The superior photoactivity is attributed to a unique surface microenvironment, which N-v increased photoelectric conversion efficiency, C-v enhanced O-2 adsorption and O-s induced center dot O-2(-) evolution with similar to 100% selectivity. Moreover, PVDF membrane-supported CNON6 (11.33 cm(2), 0.88 mg/cm(2)) can completely remove TC from wastewater at a rate of 2.62 mg/h in a simulated industrial continuous flow cell. The cost-effectiveness assessment was $6.36/kg/h, implying the CNON6/PVDF has a bright application prospect in wastewater treatment. This work developed a surface microenvironment tailor strategy to design photocatalysts for efficient degradation of TC.