The　development　of　catalysts　that　effectively　activate　target　pollutants　and　promote　their　complete　conversion　is　an　admirable　objective　in　the　environmental　photocatalysis　field.　In　this　work,　graphitic　carbon　nitride　(g-C3N4)　microtubes　with　tunable　N-vacancy　concentrations　were　controllably　fabricated　using　an　in　situ　soft-chemical　method.　The　morphological　evolution　of　C3N4　from　the　bulk　to　the　porous　tubular　architecture,　is　discussed　in　detail　with　the　aid　of　time-resolved　hydrothermal　experiments.　We　found　that　the　NO　removal　ratio　and　apparent　reaction　rate　constant　of　the　g-C3N4　microtubes　were　1.8　and　2.6　times　higher　than　those　of　pristine　g-C3N4,　respectively.　By　combining　detailed　experimental　characterization　and　density　functional　theory　calculations,　the　effects　of　N-vacancies　in　the　g-C3N4　microtubes　on　O-2　and　NO　adsorption　activation,　electron　capture,　and　electronic　structure　were　systematically　investigated.　These　results　demonstrate　that　surface　N-vacancies　act　as　specific　sites　for　the　adsorption　activation　of　reactants　and　photoinduced　electron　capture,　while　enhancing　the　light-absorbing　capability　of　g-C3N4.　Moreover,　the　porous　wall　structures　of　the　as-prepared　g-C3N4　microtubes　facilitate　the　diffusion　of　reactants,　and　their　tubular　architectures　favor　the　oriented　transfer　of　charge　carriers.　The　intermediates　formed　during　photocatalytic　NO　removal　processes　were　identified　by　in　situ　diffuse　reflectance　infrared　Fourier　transform　spectroscopy,　and　different　reaction　pathways　over　pristine　and　N-deficient　g-C3N4　are　proposed.　This　study　provides　a　feasible　strategy　for　air　pollution　control　over　g-C3N4　by　introducing　N-vacancy　and　porous　tubular　architecture　simultaneously.