Artificial Spherical Chromatophore Nanomicelles for Selective CO2 Reduction in Water

In nature, photosynthetic organelles harness solar radiation to produce energy-rich compounds from water and atmospheric CO 2 via exquisite supramolecular assemblies. Although artificial photocatalytic cycles have been shown to occur at higher intrinsic efficiencies, the low selectivity and stability in water for multi-electron CO 2 reduction hamper their practical applications. The creation of water-compatible artificial photocatalytic systems mimicking the natural photosynthetic apparatus for selective and efficient solar fuel production represents a major challenge. Here we show a highly stable and efficient artificial spherical chromatophore nanomicelle system self-assembled from Zn porphyrin amphiphiles with a Co catalyst in water for CO 2 -to-methane conversion with a turnover number >6,600 and 89% selectivity over 30 days. The hierarchical self-assembly induced a spherical antenna effect that could facilitate the photocatalytic process with an initial 15% solar-to-fuel efficiency. Furthermore, it has a capability to efficiently reduce atmospheric CO 2 into methane with high selectivity in water.