Strong Interaction between Two-Unit-Cell Heterostructure Layers Realigns Defect Energy Level for Methanol Photosynthesis

The photocatalytic conversions of CO₂ and H₂O offer a sustainable approach to provide methanol as a fuel and life-essential O₂. However, the reaction efficiency is challenged by charge recombination and sluggish reaction kinetics. This work synthesizes single-unit-cell MoS_2-<i>x</i> and organomanganese complex (MnBO) layers. The strong interaction between MoS_2-<i>x</i> and MnBO gives rise to an atomic-layered heterostructure (MnBO/MoS_2-<i>x</i>) with substantial electron transfer through the Mn-S bindings at the interface. This heterostructure achieves a methanol yield of 1.48 mmol g^-1 h^-1 with a selectivity of 99.7% at 50 °C and 0.1 MPa. The analysis reveals that the electron arrangement modulates the defect level in the band of MnBO/MoS_2-<i>x</i> and obtains polarized electrons at high potential, which not only enhances the lifetime of photogenerated charges but also reduces the barriers of CO₂ activation and hydrogenation of *CHO toward methanol. Moreover, outdoor solar-driven measurements with a homemade panel reactor demonstrate a methanol production rate of 143.2 mmol m^-2 per day and a solar-to-methanol efficiency of 0.76% under ∼0.4 sunlight irradiation without secondary energy input.