Trimetallic MOFs-derived Fe-Co-Cu oxycarbide toward peroxymonosulfate activation for efficient trichlorophenol degradation via high-valent metal-oxo species

•High-valent metals were identified as the main reactive species.•Cu doping shifted the activation mechanism from radical to non-radical pathway.•Electron extraction by Fe and Co led to the formation of electron-depleted Cu(III).•FeCoCu-NC5/peroxymonosulfate system realized effective trichlorophenol degradation.•FeCoCu-NC5/peroxymonosulfate system exhibited high peroxymonosulfate utilization.