Low-temperature　direct　ammonia　fuel　cell　(DAFC)　can　easily　transform　the　chemical　energy　into　green　in-commission　power,　yet　remains　great　challenging　due　to　kinetically　sluggish　ammonia　oxidation　reaction　(AOR).　The　interface　engineering　is　a　promising　strategy　to　take　advantage　of　synergistic　proficiencies　and　electronic　properties,　which　was　widely　applied　in　heterogeneous　catalysis　but　rarely　studied　in　AOR.　Herein,　non-oxide-based　metal–metal　carbide　interfaces　were　employed　to　construct　excellent　AOR　catalysts.　The　as-built　Pt/WC　and　PtIr/WC　catalysts　with　the　excellent　peak　current　densities　of　96.5　and　61.7　A　gPGM−1,　respectively,　which　are　over　3.5-fold　and　2.7-fold　than　those　of　carbon-supported　catalysts.　Both　experimental　and　theoretical　studies　reveal　that　the　charge　transfer　between　PtIr　NPs　and　WC　regulates　the　work　function　and　d-band　center　of　catalysts　and　further　alters　adsorption　energies　of　intermediates.　The　WC　also　plays　an　important　role　for　water　dissociation　and　hydroxyl　group　activation.　Based　on　the　understanding,　maximizing　active　interfaces　by　dispersing　PtIr–WC　composites　onto　CNTs　(PtIr–WC/CNT)　achieves　a　compelling　peak　power　density　of　140.0　mW　cm−2　at　80　°C　in　a　DAFC　test,　which　is　at　the　top　of　previously　reported　catalysts　at　similar　conditions.　Our　study　provides　a　way　to　design　highly-active　catalysts　for　AOR　and　DAFC　by　interface　engineering.　©　2022　Elsevier　Inc.