3D-printed MoS_(2)/Ni electrodes with excellent electro-catalytic performance and long-term stability for dechlorination of florfenicol

Here,we report the production of 3D-printed MoS_(2)/Ni electrodes(3D-MoS_(2)/Ni)with longterm stability and excellent performance by the selective laser melting(SLM)technique.As a cathode,the obtained 3D-MoS_(2)/Ni could maintain a degradation rate above 94.0%for forfenicol(FLO)when repeatedly used 50 times in water.We also found that the removal rate of FLO by 3D-MoS_(2)/Ni was about 12 times higher than that of 3D-printed pure Ni(3D-Ni),attributed to the improved accessibility of H^(*).In addition,the electrochemical characterization results showed that the electrochemically active surface area of the 3D-MoS_(2)/Ni electrode is about 3-fold higher than that of the 3D-Ni electrode while the electrical resistance is 4 times lower.Based on tert-butanol suppression,electron paramagnetic resonance and triple quadrupole mass spectrometer experiments,a“dual path”mechanism and possible degradation pathway for the dechlorination of FLO by 3D-MoS_(2)/Ni were proposed.Furthermore,we also investigated the impacts of the cathode potential and the initial pH of the solution on the degradation of FLO.Overall,this study reveals that the SLM 3D printing technique is a promising approach for the rapid fabrication of high-stability metal electrodes,which could have broad application in the control of water contaminants in the environmental field.

Development of MoS_(2)-stainless steel catalyst by 3D printing for efficient destruction of organics via peroxymonosulfate activation

Herein,a novel MoS_(2)-stainless steel composite material was first synthetized via a 3D printing method(3DP MoS_(2)-SS)for peroxymonosulfate(PMS)activation and organics degradation.Compared with MoS_(2)-SS powder/PMS system(0.37 g/(m^(2)/min)),4.3-fold higher k_(FLO)/S_(BET)value was obtained in 3DP MoS_(2)-SS/PMS system(1.60 g/(m^(2)/min),resulting from the superior utilization of active sites.We observed that 3DP MoS_(2)-SS significantly outperformed the 3DP SS due to the enhanced electron transfer rate and increased active sites.Moreover,Mo^(4+)facilitated the Fe^(2+)/Fe^(3+)cycle,resulting in the rapid degradation of florfenicol(FLO).Quenching experiments and electron paramagnetic resonance spectra indicated that·OH,SO_(4)·^(-),O_(2)·^(-)and^(1)O_(2)were involved in the degradation of FLO.The effect of influencing factors on the degradation of FLO were evaluated,and the optimized degradation efficiency of 98.69%was achieved at 1 mM PMS and pH of 3.0.Six degradation products were detected by UPLC/MS analyses and several possible degradation pathways were proposed to be the cleavage of C-N bonds,dechlorination,hydrolysis,defluorination and hydroxylation.In addition,3DP MoS_(2)-SS/PMS system also demonstrated superior degradation performance for 2-chlorophenol,acetaminophen,ibuprofen and carbamazepine.This study provided deep insights into the MoS_(2)-SS catalyst prepared by 3DP technology for PMS activation and FLO-polluted water treatment.