Semiconductor-based　photocatalysis　is　an　ideal　method　for　air　purification　by　eliminating　nitrogen　oxide　(NO).　However,　sluggish　carrier　separation,　photocatalysts　deactivation　and　incomplete　oxidation　are　significant　bottlenecks　for　photocatalytic　treatment　of　indoor　pollutant　NO.　Herein,　ZnO　with　assorted　structures　is　fabricated　and　undergoes　further　modification　for　deliberate　surface　defect　constructions.　Utilized　flux　agents　during　the　synthesis　provide　a　more　feasible　reducing　atmosphere,　under　which　spontaneous　generations　of　the　surface　vacancies　become　easier,　and　gradient　concentrations　are　precisely　controlled.　Photocatalyst　characterizations　affirm　the　successful　creation　of　surface　defects,　which　are　further　evaluated　by　solar-light-driven　NO　(ppb　level)　removal　investigations.　Results　showed　that　ZnO　rich　in　oxygen　vacancies　(V-O-rich　ZnO)　exhibited　5.43　and　1.63　times　enhanced　NO　removal　with　fewer　toxic　product　NO2　formations　than　its　counterparts　pristine　and　Vo-poor　ZnO,　respectively.　Importantly,　with　higher　V-O　on　the　unusual　nonpolar　facets,　V-O-rich　ZnO　does　not　only　display　enhanced　NO　conversion,　but　also　shows　the　unselective　NO　removal　process　by　producing　NO3-.　The　plausible　reaction　mechanisms　of　promoted　NO　conversions　are　further　investigated　based　on　the　surface　V-O,　well-positioned　band　structures,　and　enhanced　carrier　separations.　Results　showed　that　the　surface　V-O　with　gradient　concentrations　are　not　only　promoted　carrier　separation,　but　also　facilitate　molecular　oxygen　activation,　leading　to　the　generations　of　strong　oxidant　superoxide　radicals　(center　dot　O-2(-)),　and　contributing　to　the　enhanced　improved　efficiency.　Adsorption　of　small　molecules　(O-2,　H2O　and　NO)　on　the　defective　surface　was　further　investigated　by　density　functional　theory　(DFT)　calculations,　which　validated　the　successful　adsorption/activation　of　NO　and　O-2,　further　contributed　to　the　improved　NO　conversions.