Replacing　Pt-based　catalysts　with　metal-organic　frameworks　(MOFs)　derived　single-atom　catalysts　(SACs)　for　oxygen　reduction　reaction　(ORR)　has　largely　been　impeded　by　the　hidden　activity　of　SACs　due　to　the　challenges　in　exposing　unactivated　sites　and　regulating　their　electronic　states.　Here　we　demonstrate　the　synthesis　of　highly　exposed　iron　single　atoms　and　clusters　on　imidazole　frameworks　derived　carbon　(scCO(2)-FeC@FeNC)　by　super-critical　CO2　(scCO(2))　assisted　strategy.　The　scCO(2)　fluid　not　only　incises　dodecahedron　into　uniform　cubes　with　tenth　of　thickness　but　also　constructs　hierarchical　pores　in　frameworks　without　utilization　of　templates,　and　thus　in　favor　to　exposure　of　inactive　sites.　Moreover,　theoretical　simulations　disclose　that　the　adjacent　cluster　weakens　hybridization　between　occupied　d-orbitals　of　iron　for　Fe-N　moiety　and　p-orbitals　of　adsorbed　oxygen,　thereby　optimizing　adsorption-desorption　process　of　oxygenated　intermediates　and　accelerating　ORR　kinetics.　With　these　merits,　scCO(2)-FeC@FeNC　delivers　an　ORR　activity　with　half-wave　potential　of　0.91　V　in　alkaline　solution.　The　Zn-air　battery　using　scCO(2)-FeC@FeNC　as　air　cathode　has　a　specific　capacity　of　784.1　mAh　gZn(-1)　and　long-time　durability　of　200　h,　surpassing　commercial　Pt/C-based　Zn-air　battery.　This　work　provides　a　promising　approach　to　fabricate　MOF-derived　metal-N-C　ORR　electrocatalysts　with　high　performance.