Graphitic　carbon　nitride　(g-C3N4),　because　of　its　appropriate　band　gap,　is　a　prospective　option　for　photocatalytic　CO2　reduction.　Nevertheless,　the　rapid　recombination　of　photogenerated　charge　carriers　restricts　the　photocatalytic　efficiency　of　CN.　In　this　study,　a　one-step　chemical　reaction　followed　by　low-temperature　calcination　method　was　innovatively　used　to　anchor　zero-dimensional　(0D)　Ni-Fe　bimetallic　oxide　quantum　dots　(NFO　QDs)　onto　the　surface　of　two-dimensional　(2D)　porous　CN　nanosheets.　Under　visible　light　irradiation,　a　CO　yield　of　1571.55　mu　mol　g-　1　h-　1　was　achieved　by　the　composite　catalyst　(NFO　QDs/CN).　Ultraviolet　photoelectron　spectroscopy　(UPS)　and　in　situ　X-ray　photoelectron　spectroscopy　(XPS)　confirmed　the　existence　of　an　in-built　electric　field　at　the　interface　between　NFO　QDs　and　CN,　which　performed　as　a　Z-scheme　heterojunction.　Photoluminescence　spectroscopy　(PL),　electrochemical　impedance　spectroscopy　(EIS),　and　UV-visible　diffuse　reflectance　spectroscopy　(UV-Vis　DRS)　all　showed　that　improved　spatial　separation　of　photogenerated　electron-hole　pairs　and　increased　light　absorption　were　responsible　for　the　improved　photocatalytic　performance.　Moreover,　morphological　characterization　revealed　that　CN　possessed　a　lamellar　porous　structure,　coupled　with　the　small　size　of　the　NFO　QDs,　which　resulted　in　an　increased　specific　surface　area.　This　study　offers　fresh　perspectives　on　the　design　of　high-performance　CN-based　composite　photocatalysts　for　energy　production.