Artificial Spherical Chromatophore Mimicking LH2 and LH1–RC for Highly Efficient Photocatalytic Hydrogen Production with Turnover Number >667,000

Abstract

The supramolecular architecture of light-harvesting complex 2 (LH2) and light-harvesting complex 1-reaction center (LH1-RC) complexes underpins the near-unity quantum efficiency of photosynthesis in purple bacteria. Constructing artificial photosynthetic systems that structurally and functionally mimic these natural assemblies remains a critical challenge. Here, we report a spherical chromatophore nanomicelle system that mimics both LH2 and LH1-RC in water. This system is constructed through hierarchical coassembly of an amphiphilic porphyrin-based bacteriochlorophyll analogue and a cationic molecular nickel catalyst. Cryogenic electron microscopy directly resolves high-resolution ring-like structures on the nanomicelle surface, providing the first visual confirmation of the biomimetic architecture. The system achieves photocatalytic hydrogen evolution with a turnover number exceeding 667,000 over 72 h and a turnover frequency of above 9000 h-1 with an absolute hydrogen yield of 1.34 μmol─40 times greater than the nonassembled free molecular system─along with an initial external quantum efficiency of 6.8% at 435 nm. This outstanding performance originates from the well-defined spatial organization of the photosensitizers and catalysts, which facilitates efficient light harvesting and directional energy/electron transfer. Our work establishes a promising strategy for constructing high-performance artificial photosynthetic systems through rational biomimetic design.