Design　and　construct　nanoparticles　to　develop　highly　efficient　electrocatalysts　for　energy-associated　fuel　cells　remains　a　significant　challenge.　High　cost,　slow　reaction　kinetics,　and　poor　durability　of　catalysts　are　also　essential　challenges　toward　the　commercialization　of　DEFCs.　Hence,　the　optimization　of　highly　structured　Palladium　nanocatalysts　(Pd-NCs)　with　suitable　nanostructure,　rich　surface　area,　and　excellent　electrochemical　performance　is　a　hot　area　to　explore.　Herein,　we　have　successfully　developed　monometallic　Pd-NCs　with　different　nanostructures　(nonporous,　nanoshere,　cubes,　and　unspecified　shapes)　via　altering　the　varieties　of　stabilizing　agents　(PVA,　PVP,　AA,　CTAB,　and　SOA)　for　direct　ethanol　fuel　cells　(DEFCs)　in　alkaline　medium.　The　morphological　characterization　findings　indicate　that　the　monometallic　Pd-NCs　have　ultrafine　morphologies　with　small　particle　size　and　large　surface　areas,　indicating　the　role　of　stabilizing　agents　in　regulating　structures.　The　obtained　CTAB-Pd　NCs　exhibited　promising　electrocatalytic　activity　(5429　mAmgPd-1)　toward　ethanol　oxidation　in　alkaline　medium,　which　is　outperforms　SF-Pd　NCs　(917　mAmgPd-1),　PVA-Pd　NCs　(3458　mAmgPd-1),　PVP-Pd　NCs　(3678　mAmgPd-1),　AA-Pd　NCs　(5126　mAmgPd-1),　and　SOA-Pd　NCs　(2196　mAmgPd-1).　More　impressively,　the　as-prepared　CTAB-Pd　NCs　demonstrated　greater　EOR　durability　and　a　strong　ability　to　remove　CO　poisoning　to　accelerate　the　overall　DEFC　system.　Therefore,　our　prepared　catalysts　represents　outstanding　EOR　performance　than　most　of　resent　reported　catalysts,　due　to　their　distinct　structures　and　huge　ECSA.　This　work　provides　more　insight　into　the　structure-regulated　nanocatalysts,　which　will　contribute　to　the　rational　development　of　highly-efficient　Pd-based　electrocatalysts　for　practical　application　of　DEFCs.　©　2023　Elsevier　B.V.