Deep NO oxidation to nitrate with eliminated toxic NO₂ by-production via a microwave-constructed Fe-O-C photo-Fenton...

The deep oxidation of nitric oxide (NO) into nitrate (NO₃^-) is crucial for air pollution control but remains challenging due to insufficient and unsynchronized reactive oxygen species (ROS) generation in conventional photocatalysts. Herein, we develop a microwave-assisted interfacial engineering strategy to construct a Fe-TCPP/Fe₃O₄/rGO heterostructure (FTGM-60), where Fe-O-C covalent bridges pre-constructed during the liquid-phase microwave growth and further reinforced by the subsequent solid-phase microwave shock enable rapid electron transfer and synchronize photoexcitation with the Fe²⁺/Fe³⁺ Fenton cycle. This dual-channel mechanism simultaneously generates superoxide radicals (·O₂^-) and hydroxyl radicals (·OH), driving the selective and continuous oxidation of NO into NO₃^-. As a result, FTGM-60 achieves an outstanding NO removal efficiency of 81.1 % and nitrate selectivity of 98.3 % under simulated sunlight (AM 1.5 G), while effectively suppressing toxic nitrogen dioxide (NO₂) accumulation. This microwave-driven interfacial coupling strategy establishes a new paradigm for designing strongly bonded MOF-oxide systems toward efficient photo-Fenton catalysis and environmentally benign gaseous pollutant abatement.