Highly Efficient Photoreduction of Low-Concentration CO₂ to Syngas by Using a Polyoxometalates/Ru^II Composite

At present, the fixation of CO₂ always requires it to be extracted from the atmosphere first, which leads to more energy consumption. Thus, direct photoreduction of low-concentration CO₂ to useful chemicals (e.g., syngas) under sunlight is significant from an energy-saving and environmentally friendly perspective. Here, the design and fabrication of a [Ru(bpy)₃ ]/[Co₂₀ Mo₁₆ P₂₄ ] composite is demonstrated for visible-light-driven syngas production from diluted CO₂ (3-20 %) gas with a high yield of approximately 1000 TONs (turnover number of syngas). This activity is an order of magnitude higher than the reported system with [Ru(bpy)₃ ]²⁺ participation. With evidence from ultrafast transient absorption, GC-MS, ¹ H NMR spectroscopy and in situ transient photovoltage tests, a clear and fundamental understanding of the highly efficient photoreduction of CO₂ by the [Ru(bpy)₃ ]/[Co₂₀ Mo₁₆ P₂₄ ] composite is achieved. Making use of the structure and property designable polyoxometalates towards the photo-fixation of CO₂ is a conceptually distinct and commercially interesting strategy for making useful chemicals and environmental protection.