Tuning the interface of graphite felt-supported NiCo composites for superior electrocatalytic degradation of pharmaceutical pollutants.

Pharmaceuticals are usually paid more attention because of their persistence and potential toxicity, and their degradation via different radicals is depended on their types and concentrations. In this work, an electrocatalytic system using graphite felt (GF)-supported NiCo-based catalysts as working electrodes was established for degradation of pharmaceuticals such as ibuprofen (IBU). 95.0 % and 99.8 % of IBU can be degraded under the action of NiCo-LDH@g-C3N4/GF and NiCoO2-GF systems, respectively. Correspondingly, the rate constants of two systems were 4.0 and 4.8 times higher than that of bare GF system, confirming the significant catalytic enhancement of NiCo-based composites. Notably, compared with NiCo-LDH@g-C3N4/GF system, the NiCoO2-GF system exhibited superior comprehensive performance, including lower energy consumption (0.88 kWh m-3 order-1), higher current efficiency (86.6 %), excellent removal efficiency in actual water (> 90 %), reduced by-products toxicity and good reusability over five cycles. ESR spectra and radical quenching tests verified that hydroxyl radicals dominated the IBU degradation process in the NiCoO2-GF system. Combined with DFT calculations, 1O2 was also identified as a secondary active species involved in the degradation. These findings provide fundamental insights into the design and application of NiCo-based electrocatalytic systems for treatment of complex pharmaceutical-containing wastewater.