Encapsulating Co and Pd Nanoparticles as Spatially Separated Dual Active Sites for Heterogeneous Persulfate Activation: Synergistic Catalysis and Switching of the Primary Reaction Pathway

This study demonstrates that the carbon encapsulation of Pd and Co as spatially isolated redox-active sites can synergistically enhance the activation of peroxymonosulfate (PMS) and peroxydisulfate (PDS) and enable persulfate precursor-sensitive degradation routes. The superiority of bimetal–carbon composites (i.e., Pd/Co@NC) was confirmed based on a higher efficiency of Pd/Co@NC with varying Pd/Co ratios for persulfate activation than the sum of efficiencies of single metal-component catalysts applied at corresponding dosages. Treatment performances of Pd/Co@NC with different metal compositions aligned with the dependence of electrical conductivity and binding affinity of Pd/Co@NC on the relative metal content. Reflecting differential reactivity of monometallic components toward persulfate, the primary degradation pathway was switched, depending on the persulfate type. Pd/Co@NC caused r…