An artificial photocatalyst with a Rh complex immobilized onto polymeric carbon nitride (CN) through non-covalent interaction was constructed for photocatalytic NADH regeneration. DFT calculations verified the adsorption of the bipyridine ligand onto the CN photocatalyst. By further coupling the in situ formed NADH with FDH immobilized on a hydrophobic membrane, an enhanced HCOOH production (3.1 mM) from CO2 could be realized on the gas-liquid-solid three-phase interface. This work provides an alternative and efficient strategy for promoting artificial photosynthesis.