In　order　to　overcome　the　low　catalytic　efficiency　of　conventional　single　cobalt-based　catalysts,　a　cobalt-based　peroxymonosulfate　(PMS)　heterogeneous　catalyst,　named　P-Co@C,　was　synthesized　by　introducing　phosphorus.　The　degradation　rate　of　diclofenac　(DCF)　was　increased　by　5-fold　from　0.076　min-1　(Co@C)　to　0.426　min-1　(P-Co@C).　The　enhanced　catalytic　behavior　was　ascribed　to　the　increased　specific　area,　promotional　hydrophilicity,　reduced　resistance　to　electron　transfer　and　improved　electron　donor　of　reductive　phosphorus.　Density　functional　theory　(DFT)　calculations　suggest　that　the　doped　P　further　facilitates　the　adsorbability　and　charge　transfer　intensity　between　catalyst　and　PMS,　which　benefits　the　generation　of　hydroxyl　radical,　sulfate　radical　and　singlet　oxygen.　Furthermore,　toxicity　assessment　of　the　intermediates　revealed　that　the　P-Co@C/　PMS/DCF　system　was　a　diminishing　toxicity　process,　revealing　the　practicability　and　eco-friendly　of　P-Co@C　in　PMS-based　oxidation　process.　This　work　provides　a　new　strategy　for　exploring　the　cation　and　anion　co-activation　of　the　PMS　heterogeneous　catalytic　systems.