To simultaneously enhance the catalytic activity of Pd and lower its dosage, we report a Pd/Co-MOF nanosheets/Ni foam electrode (Pd/Co-MNSs/Ni foam) with conductive 2D MOF nanosheets as interlayer for electrocatalytic hydrodechlorination (ECH). Such electrode delivers high ECH activity for nearly complete dechlorination (~97%) of chloramphenicol (CAP) with an apparent rate constant of 0.11 min⁻¹, outcompeting the well-reported and the commercial electrode materials. Pd/Co-MNSs/Ni foam maintains its activity after 9 consecutive runs and 5-day exposure to air, and shows rapid degradation kinetics for other priority contaminants. The formation of Pd/Co-MNSs heterojunction interface increases the electron density of metallic Pd and brings the d states closer to Fermi level than Pd alone, thus optimizing the binding of ECH intermediates. This support construction-based strategy tunes the interface of catalytic electrode to expose active sites and modulate the electronic states of catalyst to promote intrinsic activity, boosting electroreductive remediation of organic halides.