Ultrafine palladium nanoparticles supported on 3D self-supported Ni foam for cathodic dechlorination of florfenicol

Electrocatalytic hydrodechlorination is deemed as a promising environmental remediation technology for fast and effective detoxification of halogenated antibiotic pollutants. In this study, a novel nickel (Ni) foam electrode decorated by ultrafine palladium (Pd) nanoparticles (denoted as Pd@Ni-foam) was reported for electrocatalytic dechlorination of florfenicol (FLO, a typical antibiotic). The Pd@Ni-foam electrode was synthesized via a facile and simple spontaneous galvanic replacement of surface Ni atoms of Ni foam with Pd precursor. The obtained Pd@Ni-foam catalyst showed an excellent performance on electrochemical dechloridation of FLO. The dechloridation efficiency of FLO (20 mg L-1) reached 99.5% with the dechloridation rate as fast as 16.58 mg min(-1) at cathode potential of -1.2 V (vs. saturated Ag/AgCl), which far prevailed over pure Ni foam (2.63 mg min(-1)) and commercial Pd/C (11.32 mg min(-1)). The reaction rate constant (0.044 min(-1)) of FLO dechloridation at Pd@Ni-foam electrode was 44 and 4.4 times higher than that of pure Ni-foam (0.001 min(-1)) and commercial Pd/C (0.010 min(-1)), respectively. The excellent electrocatalysis for FLO dechloridation of Pd@Ni-foam cathode is ascribed to the 3D self-supported Ni-foam frame for mass transfer enhancement and the formation of Pd-Ni micro-interfaces leading to the high utilization of atomic H*. Furthermore, the toxicity assessment showed that the antibacterial activity of FLO was complete elimination after electrocatalytic dechlorination process.