In　this　study,　pyrochlore　Pr2B2O7　oxides　(B[dbnd]Zr,　ZrSn,　Sn,　PZO/PZSO/PSO)　and　perovskite　(B[dbnd]Ti,　PTO)　were　prepared　as　direct　ammonia　solid　oxide　fuel　cell　(DA-SOFC)　cathode　with　oxygen　reduction　reaction　activity　induced　by　B-site　cationic　defects.　Compared　with　PTO,　the　pyrochlore　PBO　with　unoccupied　8a-oxygen　sites　are　high　in　inherent　oxygen　vacancies　(ca.　12.5%),　leading　to　enhanced　migration　of　lattice　oxygen.　Among　the　n-type　semiconductors,　PZO　is　with　a　more　negative　flat-band　potential　and　is　more　effective　in　terms　of　overcoming　energy　barriers.　As　a　result,　the　conductivity　of　PZO　is　two　orders　of　magnitude　higher　than　that　of　PTO　at　800　°C.　The　oxygen　transport　performance　reveals　that　the　surface　exchange　coefficient　of　PZO　is　about　one　order　of　magnitude　higher　than　that　of　La0.7Sr0.3MnO3-δ　at　900　°C.　Owing　to　high　conductivity,　fast　oxygen　transport,　and　matched　thermal　expansion　coefficient,　an　anode-supported　DA-SOFC　using　the　PZO-based　cathode　can　offer　a　maximum　power　density　of　0.25　W　cm−2　at　600　°C　and　1.22　W　cm−2　at　800　°C,　operating　continuously　over　100　h　without　obvious　degradation.　The　electrochemical　performance　is　2.3　folds　higher　than　those　of　SOFCs　using　other　PBO-based　cathode,　and　higher　than　most　reported　SOFCs　with　the　cathodes　using　A-site　Pr.　©　2021　Elsevier　B.V.