Synthesis of carbon dots with tailored heteroatomic structure for achieving ultrahigh effectiveness in persulfate activation

Abstract

Carbon dots (CDs) are normally feature with zero-dimensional structure, excellent solubility, good biosafety, and exceptional photoelectronic properties, thus, awakening the homogeneous-like photocatalytic potency of CDs in peroxymonosulfate (PMS) activation can afford new idea for water body remediation. Herein, we presented a facile nitrogen and sulfur co-doping strategy for the development of high-performance CDs-based photocatalysts. Through the deep investigation on the structure-activity relationship, we proposed that the incorporated pyridinic N within CDs structure could serve as efficient Lewis basic sites for PMS confinement. Importantly, the co-existence of oxidized sulfur groups and specific nitrogen speciation (pyridine N and pyrrolic N) induced unique “push-pull” effect on the photogenerated carriers within the surface state of S,N co-doped CDs. The unique synergy sites and surface hydrophilic nature conferred the CDs exceptional photocatalytic effectiveness, presenting a remarkable PMS consumption ratio of 7.62 per gram of the CDs photocatalyst within just 20 min. Profited from the improved kinetics of interfacial reactions, the CDs-photocatalyzed oxidation system that consisted largely of sulfate radicals can completely degrade rhodamine B within 12.5 min, and hold great potential in long-term operation without needing to regenerate CDs catalyst.