Hierarchically ordered CNTs encapsulating Ni-polyoxometalate with exterior Fe-porphyrin enable vectorial charge transfer for efficient CO2 photoreduction.

In natural photosynthesis, compartmentalized protein networks spatially orchestrate light-driven electron transfer for CO2 activation, offering a blueprint for artificial systems. Herein, we report the design and synthesis of a molecular compartmentalized photocatalyst for photocatalytic CO2 overall conversion, in which a nickel-substituted polyoxometalate (NiPOM) is confined within the inner channels of carbon nanotubes (CNTs), while Fe-porphyrin derivatives (FeTCPPOMe) are anchored onto the CNT exterior via π-π interactions. This unique inside-outside configuration creates a highly ordered, vectorial electron transfer pathway whereby photoexcited electrons are generated at the FeTCPPOMe sites, swiftly injected into the CNT and then directly delivered to the encapsulated NiPOM. Under simulated solar illumination, the FeTCPPOMe-NiPOM@CNT composite exhibits good photocatalytic CO2 reduction performance, achieving a CO production rate of 42.7 μmol g-1 h-1 with a 100% CO selectivity. In-situ DRIFTS, quasi in-situ XPS and in-situ illuminated Kelvin probe force microscopy (KPFM) combined with density functional theory calculations clearly elucidated the photoinduced electron transfer pathway. This work demonstrates that strategic nanoscale confinement and hierarchical assembly can dramatically enhance charge transport and catalytic efficiency, offering a promising blueprint for next-generation CO2 photoreduction systems.