Iron-cobalt phosphide nanoarrays grown on waste wool-derived carbon: An efficient electrocatalyst for degradation of tetracycline

Electrocatalytic oxidation is regarded as one of the most promising technologies for antibiotic-contaminated wastewater remediation. However, a rational design of cost-effective, green and efficient earth-abundant electrocatalysts is still a big challenge. Herein, a novel hierarchical porous hybrid is constructed by iron-cobalt phosphide (FeCoP) nanoarrays grown on waste wool-derived carbon and applied as anode for electrooxidative degradation of tetracycline hydrochloride (TCH). In the process, the activated N, S self-doped biomass carbon (NSC) is fabricated from waste wool using K2FeO4 as pore-forming agent, graphitization agent and iron source. The nanoarray-like Fe-Co layered double hydroxides (FeCo LDH) are then in-situ grown on activated biomass carbon surface under mild reaction conditions. Simple further phosphatization converts FeCo LDHs to FeCoP nanoarrays. The as-prepared FeCoP/NSC hybrid possesses a hierarchical porous structure with abundant active sites, as well as the weakened oxygen evolution performance and the fast charge transfer between FeCoP-NSC interface. Benefiting from the multiple synergistic effects, the removal rate of TCH by FeCoP/NSC as anode and Pt as cathode exceeds 95% within 60 min under the optimum conditions. Remarkably, the removal rate of TCH is nearly 100% within 60 min when the cathode is replaced with NSC. This work provides a new strategy for high-efficiency degradation of antibiotics.