Integration of Atomically Dispersed Cu-N4 Sites with C3N4 for Enhanced Photo-Fenton Degradation over a Nonradical Mechanism

Photo-Fenton degradation as a promising strategy for antibiotic wastewater treatment attracted extensive attention, while the unsatisfactory catalytic performance vitally limits its industrial application. Herein, we demonstrate that confining atomically dispersed Cu into C3N4 (Cu-C3N4) enables fast H2O2 activation and efficient separation of photogenerated electron- hole pairs, resulting in a dramatic improvement of the degradation efficiency of the Photo-Fenton reaction. Photo-Fenton degradation of ciprofloxacin (CIP) was close to 99% within 30 min over optimized Cu-C3N4, corresponding to a pseudo-first-order rate constant of similar to 0.0978 min-1, almost 4.5 times higher than pure C3N4 counterpart. The electron paramagnetic resonance, quenching experiments, and X-ray absorption fine structure results reveal that the superior Photo-Fenton catalytic performance is attributed to a nonradical reaction pathway, where the H2O2 is activated by the formation of the O=Cu-N4=O intermediate. The advanced catalyst as well as the refreshing H2O2 activation mechanism are of profound significance for the materials design in the wastewater treatment field.