Promoting photocatalytic degradation of tetracycline over in-situ grown single manganese atoms on polymeric carbon nitride

Introducing single-atom metals into polymeric carbon nitride (PCN) framework is a promising strategy to offer more active sites along with pollutant degradation kinetics. Herein, single manganese atoms decorated PCN (denoted as MCN) was fabricated via a straightforward in-situ thermopolymerization strategy using urea as PCN precursor and manganese acetylacetone as manganese (Mn) source. The as-synthesized optimal sample MCN-2 exhibits legible monatomic Mn sites on PCN framestructure and enhanced specific surface area (122.4 m(2).g(-1)). The monatomic Mn introduced via the Mn-N/O coordination is demonstrated to be able to narrow the bandgap and facilitate separation and transfer of photo-excited carriers, which has a salutary effect on visible light harvesting and MCN utilization. Consequently, the MCN-2 exerts a superior pseudo-first-order kinetic rate constant k of 0.041 min(-1) in visible-light-driven TC photodegradation, with ca. 13-fold higher than that of the pristine PCN. Further, the intermediates and reactive oxygen species (O-1(2), h(+) and center dot O-2(-)) generating in the TC photodegradation process are experimentally manifested and a plausible mechanism for TC degradation over MCN is proposed. This work not only proves the efficacy of MCN in photodegradation of TC but expands Mn to other single-atom metals for pollutant removal.

Automated summary

Introducing single-atom metals into the polymeric carbon nitride framework offers more active sites for pollutant degradation. In this study, single manganese atoms decorated PCN (MCN) was fabricated and showed enhanced photocatalytic properties and visible light absorption. The findings provide insights for exploring the application of other single-atom metals in pollutant removal.