Selective glyphosate degradation via oxygen activation using Fe-N-C: Critical role of size exclusion

Selective elimination of glyphosate (PMG) from complex water matrices remains a significant challenge. Metalnitrogen-carbon (M-N-C) materials derived from metal-organic frameworks (MOFs) offer a promising platform due to their tunable porosity and abundant active sites. In this study, three Fe-N-C-x (x = 5, 10, 20) catalysts with varying pore sizes (2-4 nm) and no surface-active sites were synthesized for PMG degradation under interference with contaminants of different sizes. The results showed Fe-N-C-5 exhibited superior catalytic and antiinterference performance for PMG degradation compared to Fe-N-C-10 and Fe-N-C-20. This was attributed to the greater accessibility of smaller-sized PMG (molecular size 0.9 nm) to the internal active sites through the pore channels, while larger-sized pollutants were effectively excluded. Zeta potential measurements and in situ ATRFTIR spectroscopy revealed that the entrance of PMG was driven by both electrostatic interaction and coordination bonding between phosphate and Fe in Fe-N-C-5. Quenching experiments combined with electron spin