The　work　proposed　a　distinct　arrangement　to　construct　the　amperometric-type　NO2　sensor　using　pyrochlore-phase　Pr2Zr2O7　as　oxygen-defect　conductor.　An　effective　co-doping　strategy　at　A　and　B　sites　was　explored　to　prepare　the　defective　Pr2-xMxZr1.95In0.05O7+delta　(PMZI,　M　=　Ca,　Sr,　Ba)　oxygen　conductors.　DFT　results　show　that　the　band　structure　of　solid　electrolyte　are　dependent　of　the　doping　elements　at　A　and　B　sites.　A-site　doping　theoretically　causes　48f　and　8b　oxygen　defects,　yet　only　48f　oxygen　defect　for　B-site　doping.　Oxygen　defect　energy　shows　that　Ca2+　doping　at　A　site　can　be　inclined　to　8b　oxygen　defects,　as　opposed　to　Sr2+　and　Ba2+　incorporation　that　can　cause　migratable　48f　oxygen　defects.　DFT　simulation　indicates　that　the　thermally　excited　electrons　for　the　Ca2+　doping　are　uneasier　to　enter　the　conduction　band　through　two　deeper　impurity　levels,　compared　to　Sr2+　and　Ba2+　doping,　as　the　dark　current　is　lower　for　the　PCZI　sensors.　The　oxygen-defect　induces　both　the　electron　transport　and　enhanced　NO2　sensing　performances.　The　result　of　amperometric　response　obviously　exhibits　that　the　Delta　I　value　of　the　optimized　PCZI　(0.02)　sensor　with　high　sensitivity　(224　nA/ppm)　is　15.11　and　12.26　times　as　high　as　the　pure　Pr2Zr2O7　and　commercial　YSZ　sensors,　respectively,　exhibiting　the　potential　industrial　application　prospect.　(c)　2018　Elsevier　Ltd.　All　rights　reserved.