Nitrate　reduction　in　bio-electrochemical　systems　(BESs)　has　attracted　wide　attention　due　to　its　low　sludge　yields　and　cost-efficiency　advantages.　However,　the　high　resistance　of　traditional　electrodes　is　considered　to　limit　the　denitrification　performance　of　BESs.　Herein,　a　new　graphene/polypyrrole　(rGO/PPy)　modified　electrode　is　fabricated　via　one-step　electrodeposition　and　used　as　cathode　in　BES　for　improving　nitrate　removal　from　wastewater.　The　formation　and　morphological　results　support　the　successful　formation　of　rGO/PPy　nanohybrids　and　confirm　the　part　covalent　bonding　of　Py　into　GO　honeycomb　lattices　to　form　a　three-dimensional　cross-linked　spatial　structure.　The　electrochemical　tests　indicate　that　the　rGO/PPy　electrode　outperforms　the　unmodified　electrode　due　to　the　3.9-fold　increase　in　electrochemical　active　surface　area　and　6.9-fold　decrease　in　the　charge　transfer　resistance　(Rct).　Batch　denitrification　activity　tests　demonstrate　that　the　BES　equipped　with　modified　rGO/PPy　biocathode　could　not　only　achieve　the　full　denitrification　efficiency　of　100%　with　energy　recovery　(15.9　×　10−2　±　0.14　A/m2),　but　also　favor　microbial　attach　and　growth　with　improved　biocompatible　surface.　This　work　provides　a　feasible　electrochemical　route　to　fabricate　and　design　a　high-performance　bioelectrode　to　enhance　denitrification　in　BESs.　©　2024　Elsevier　Inc.