An electrosorption-assisted porous carbonaceous electrode for simultaneous H2O2 in situ generation and ciprofloxacin removal

• C-O-C and COOH groups in HNO 3 -treated RVC serve as key active sites for enhanced 2e − ORR. • Synergistic effects of electrosorption and degradation enable rapid and efficient CIP removal. • Certain degradation products exhibit increased toxicity and improved biodegradability compared to CIP. • SO 4 - and 1 O 2 act as the dominant reactive species for CIP degradation. Carbonaceous materials are considered promising electrode materials for H 2 O 2 electrosynthesis and wastewater treatment. However, the structural design and modification of effective carbonaceous electrodes for simultaneous H 2 O 2 formation and pollutant degradation remain challenging. Herein, a reticulated vitreous carbon (RVC) electrode with an intrinsic three-dimensional porous structure was fabricated. The functional groups, defects and air-liquid-solid triple-phase interfaces were further incorporated into RVC by facile HNO 3 oxidation (HNO 3 -RVC), which was identified via X-ray photoelectron spectroscopy and contact angle tests. Compared with its pristine counterpart, HNO 3 -RVC yielded 1.5 times the one-hour cumulative H 2 O 2 concentration and 1.8 times the current efficiency. Furthermore, HNO 3 -RVC exhibited a 2-fold increase in ciprofloxacin (CIP) removal due to the synergistic effect of fast electrosorption and degradation. The incorporated C-O-C/COOH and defects are proposed to provide active sites for H 2 O 2 formation, and triple phase interfaces could transfer both dissolved and gaseous oxygen for H 2 O 2 formation. Scavenging tests indicated that ·SO 4 - and 1 O 2 act as the dominant reactive species for CIP degradation. Toxicity experiments suggested that some degradation products may exhibit greater toxicity than the parent CIP does, while prolonging the treatment time could reduce the toxicity.