The　low　carrier　concentration　and　sluggish　internal　charge　migration　impede　the　efficiency　of　CO2　photoreduction　in　conventional　catalysts.　Herein,　we　present　an　efficient　electron　beam　irradiation　strategy　to　synthesize　a　carbon　nitride/carbon　quantum　dots　(ECN/CQD)　heterojunction　photocatalyst　with　an　N-bridged　covalent　interface.　This　covalent　bond　at　the　ECN/CQD　interface　significantly　accelerates　the　separation　and　migration　of　photogenerated　charge　carriers,　resulting　in　a　high　concentration　of　surface　charges.　As　a　result,　ECN/CQD　demonstrates　outstanding　photocatalytic　performance,　with　CO　and　CH4　evolution　rates　of　44.5　and　0.88　μmol　g−1　h−1,　respectively,　and　excellent　stability　across　eight　consecutive　cycles.　Additionally,　in　situ　Kelvin　probe　force　microscopy　and　electrostatic　force　microscopy　characterizations　reveal　the　charge　distribution　on　the　catalyst　surface,　providing　deep　insights　into　the　enhanced　charge　separation　capabilities　of　the　covalent　bond　heterojunction.　This　work　provides　an　innovative　approach　for　developing　high-performance　covalent　bond　heterojunction　photocatalysts　for　efficient　CO2　reduction.　©　2025　Elsevier　Ltd