AbstractMo₂C MXene (Mo₂CT_x) is one of the most promising noble‐metal‐free cocatalysts for photocatalytic H₂ production because of its excellent electron transport capacity and abundant Mo sites. However, Mo₂CT_x typically exhibits a strong Mo─H_ads bond, resulting in that the produced H₂ difficultly desorbs from the Mo surface for the limited activity. To effectively weaken the Mo─H_ads bond, in this paper, a regulation strategy of electron donor Au releasing electrons to the d‐orbitals of Mo sites in Mo₂CT_x is proposed. Herein, the Mo₂CT_x‐Au/CdS photocatalysts are prepared through a two‐step process, including the initial loading of Au nanoparticles on the Mo₂CT_x surface and the subsequent in situ growth of CdS onto the Mo₂CT_x‐Au surface. Photocatalytic measurements indicate that the maximal H₂‐production rate of Mo₂CT_x‐Au/CdS reaches up to 2799.44 µmol g⁻¹ h⁻¹, which is 30.99 and 3.60 times higher than that of CdS and Mo₂CT_x/CdS, respectively. Experimental and theoretical data corroborate that metallic Au can transfer free electrons to Mo₂CT_x to generate electron‐enriched Mo^δ‐ sites, thus causing the increased antibonding‐orbital occupancy state and the weakened Mo─H_ads bond for the boosted H₂‐production efficiency. This research provides a promising approach for designing Mo₂CT_x‐based cocatalysts by regulating the antibonding‐orbital occupancy of Mo sites for improved photocatalytic performance.