Cobalt-based electrocatalytic membrane with integrated catalytic network for efficient dehalogenation

Electrochemical reductive dehalogenation is a promising strategy for removing halogenated antibiotics. However, its practical application remains limited by inefficient active-site utilization, sluggish mass transport, and the insufficient stability of conventional electrocatalysts. Here, we develop a cobalt-based electrocatalytic membrane (Co-EM) that integrates a coupled catalytic network within a porous flow-through architecture to address these challenges. Uniformly dispersed cobalt nanoparticles and single atoms are anchored within an aramid nanofiber framework. This design enables synergistic catalytic interactions while promoting convective transport and interfacial contact with pollutants. As a result, the Co-EM system achieves 98.6% removal of florfenicol (FLO) at a current density of 2 mA cm^-2 and a permeate flux of 25.5 L m^-2 h^-1. Experimental results and DFT calculations demonstrate that the coupled catalytic network enhances pollutant adsorption, promotes efficient charge transfer, and lowers the reaction energy barrier for carbon-halogen bond cleavage, thereby favoring a direct electron transfer (DET)-dominated pathway. The Co-EM further exhibits broad applicability to diverse halogenated pollutants (>95% removal), substantial detoxification of transformation products, and stable operation in real surface water. It maintains > 85% removal efficiency with Co leaching < 0.002 ppm during continuous operation. These results demonstrate a membrane-electrocatalyst design strategy that couples catalytic-site synergy with flow-through mass transfer, offering a promising route for practical electrochemical dehalogenation in complex water environments.