Enhanced peroxymonosulfate decomposition into ?OH and 1O2 for sulfamethoxazole degradation over Se doped g-C3N4 due to induced exfoliation and N vacancies formation

The development of low-cost and facile synthesized metal-free peroxymonosulfate (PMS) activation catalysts is paramount important for the practical remediation of organic pollution caused by antibiotics. Graphitic carbon nitride (g-C3N4) as a promising alternative, to improve its PMS activation performance, we proposed an efficient method to prepare exfoliated Se doped g-C3N4 (Se-g-C3N4) with 0.095 wt% Se and more exposed reactive N vacancies through the thermal polycondensation of melamine and Se powder at 550 ?. The results proved that 93.0% of sulfamethoxazole (SMX) can be degraded over Se-g-C3N4 with PMS in 180 min, and the corresponding degradation rate constant of 0.0149 min? 1 was even 4-fold higher than that of bulk g-C3N4 (0.0039 min-1). It was found that more 1O2 was generated and ?OH was further identified because of the enhanced PMS selfdecomposition process, especially PMS reduction via electron transfer from Se-g-C3N4. The introduction of Se atom in g-C3N4 structure not only induced the formation of nitrogen vacancies to modulate the electron distribution of g-C3N4, but also favored the exfoliation of inter-facial stacking to increase the exposure of active sites due to the large atomic radius of Se. Hence, this work offered a new strategy for improving the PMS activation performance of g-C3N4 by regulating its electron deficiency and exposing more reactive N vacancies simultaneously.

Automated summary

The introduction of selenium into graphitic carbon nitride (g-C3N4) can enhance its performance in activating peroxymonosulfate (PMS), leading to more efficient degradation of organic pollution caused by antibiotics. The Se-doped g-C3N4 (Se-g-C3N4) showed a significant increase in degradation rate compared to bulk g-C3N4, attributed to the enhanced PMS decomposition and electron transfer process. This work provides a new strategy for improving the PMS activation performance of g-C3N4 by regulating electron distribution and increasing exposure of reactive sites.