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Photocatalytic nitrogen fixation has attracted much attention because of its ability to synthesize ammonia under mild conditions. However, the ammonia yield is still greatly limited by the sluggish charge separation and extremely high N₂ dissociation energy. Herein, two-dimensional Ti₃C₂ MXene ultrathin nanosheets were introduced to construct Ti₃C₂/TiO₂ composites via electrostatic adsorption for photocatalytic nitrogen fixation. The photocatalytic activity experiments showed that after adding 0.1 wt% Ti₃C₂, the ammonia yield of the Ti₃C₂/TiO₂ composite reached 67.9 μmol L⁻¹ after 120 min of light irradiation, nearly 3 times higher than that of the monomer TiO₂. XPS, DRS, LSV, and FTIR were used to explore the possible photocatalytic nitrogen fixation mechanism. Studies showed that a close interfacial contact has been formed via the bonding mode of =C-O between the Ti₃C₂ and TiO₂ samples. The formed =C-O bond boosts an oriented photogenerated charge separation and transfer in the Ti₃C₂/TiO₂ composite. This work provides a promising idea for constructing other efficient MXene-based composite photocatalysts for artificial photosynthesis.