MOF-derived CeO2/NiFe2O4@MXene electrocatalysts for efficient seawater electrolysis and ciprofloxacin photodegradation

Developing cost-effective, durable, and highly efficient bifunctional electrocatalysts for alkaline natural seawater (ASW) electrolysis remains a significant challenge. In this study, metal–organic frameworks (MOF)–derived NiFe 2 O 4 (MNF), NiFe 2 O 4 @MXene (NFMX), and x% CeO 2 /NiFe 2 O 4 @MXene (x = 2.5, 5, and 7.5 wt%; denoted as 1-CNFMX, 2-CNFMX, and 3-CNFMX, respectively) with abundant oxygen vacancies were synthesized via an in-situ solvothermal method. The electrocatalytic performance of the synthesized materials was investigated in an ASW electrolyte. Among them, the 2-CNFMX@nickel foam (NF) electrode exhibited outstanding bifunctional activity, with low overpotentials (η) of 240 mV and 340 mV at current densities (J) of 10 and 100 mA/cm 2 for the oxygen evolution reaction (OER), and 41 mV and 192 mV at 10 and 100 mA/cm 2 for the hydrogen evolution reaction (HER), respectively. These results outperform those of benchmark electrodes IrO 2 @NF and Pt/C@NF. In addition, the system achieved high Faradaic efficiencies of ~96.24 % for OER and ~97.31 % for HER, demonstrating its potential for large-scale industrial applications. Furthermore, the 2-CNFMX material exhibited remarkable photocatalytic activity, achieving 99 % degradation of ciprofloxacin under white light-emitting diode irradiation. This work presents a promising strategy for developing multifunctional catalysts capable of efficient seawater electrolysis and simultaneous degradation of pharmaceutical contaminants in wastewater. • CNFMX composites were synthesized using an in situ solvothermal method. • The 2-CNFMX showed low η: 41 mV (HER) and 240 mV (OER) at 10 mA/cm 2 in ASW. • The 2-CNFMX achieved 99 % ciprofloxacin degradation under LED illumination. • The 2-CNFMX composite demonstrated exceptional cyclic stability in both catalytic systems. • High faradaic efficiencies were obtained: ~96.24 % for OER and ~97.31 % for HER.