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 MoS2-x and organomanganese complex (MnBO) layers. The strong interaction between MoS2-x and MnBO gives rise to an atomic-layered heterostructure (MnBO/MoS2-x) 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/MoS2-x 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.