Efficient Visible‐Light‐Driven CO₂ Reduction Enabled by a Triazatriangulenium Organic Sensitizer and Iron Molecular Catalyst

Abstract The development of efficient photocatalytic systems based on earth‐abundant metals for the direct conversion of CO 2 into renewable solar fuels is transforming the landscape of solar energy conversion. In this study, we present a novel photocatalytic system utilizing the triangulenium dye ( N,N′,N′′ ‐tris(2‐hydroxyethyl)‐triazatriangulenium ( TATH ) hexafluorophosphate) as the organic photosensitizer, paired with an iron‐quaterpyridine molecular catalyst and BIH/TEOA as sacrificial electron donors. The photocatalytic performance is significantly enhanced through a synergistic electron‐proton relay mechanism between BIH and TEOA, which effectively mitigates charge recombination during CO 2 reduction. Operated in a MeCN/NaHCO 3 buffer under visible light, this system demonstrates exceptional activity and selectivity for CO production, achieving a turnover number (TON) exceeding 20,000, a quantum yield of 41.6%, and >99% product selectivity. These results surpass benchmark systems employing noble‐metal photosensitizers such as [Ru(bpy) 3 ] 2+ or [Ir(bpy)(ppy) 2 ] + under identical conditions. Remarkably, both the photosensitizer and catalyst maintain exceptional operational stability by their high individual TONs. This versatile, noble‐metal‐free system holds great potential for advancing direct solar‐to‐fuel photocatalytic CO 2 reactions.