Journal Article Review Fenton‐like reaction Fenton‐like reactions alloyed quantum rods boosted charge dynamics carbon nitride catalysis electron transfer pathway energy conversion environmental decontamination heavy-metal-free mononuclear metal molecular complexes multi-interfacial order-disorder homojunction nitrogen species noble-metal-free nonradical pathway oxygen evolution reaction peroxymonosulfate photocatalysis photocatalytic H2O2 production redox reactions single atom catalysis single atom catalysts single‐atom catalysts size‐dependent structural phases structure‐activity relations tailored reactive sites transition metals