Designing　porous　structures　has　proven　to　be　an　effective　strategy　for　enhancing　the　photocatalytic　NO　oxidation　activity　of　carbon　nitride　(CN).　Despite　significant　advances　in　the　fabrication　of　porous　CN,　a　cost-effective　and　high-yield　synthesis　method　for　porous　CN　is　still　highly　desirable.　In　this　study,　we　presented　a　facile　strategy　to　synthesize　porous　carbon　nitride　by　V2O5-assisted　thermal　oxidation　process.　Namely,　after　grinding　bulk　CN　with　a　small　amount　of　NH4VO3,　the　mixture　was　subjected　to　thermal　treatment,　resulting　in　porous　carbon　nitride　with　a　yield　of　50　%.　The　resulting　porous　structure,　which　features　an　enlarged　surface　area　and　enhanced　charge　separation　efficiency,　significantly　improved　the　photocatalytic　performance　for　NO　removal-approximately　four　times　higher　than　bulk　CN.　Additionally,　the　NO　removal　mechanism　was　investigated　through　in-situ　Fourier　transform　infrared　spectroscopy　to　observe　reaction　intermediates　and　electron　paramagnetic　resonance　trapping　experiments　to　identify　active　species,　providing　insight　into　the　conversion　pathway.　The　catalytic　thermal　oxidation　etching　process　effectively　tuned　the　microstructure　of　g-C3N4,　offering　a　low-cost,　easy-to-implement,　and　time-efficient　method　for　synthesizing　porous　CN,　thereby　providing　a　promising　approach　for　developing　advanced　photocatalysts.