Interfacial electronic reconstruction and charge-transfer kinetics in colloidally assembled S-scheme MoSe2/porphyrin heterostructures for solar water splitting.

Rational interfacial engineering of organic-inorganic heterostructures is pivotal for advancing solar-driven water splitting. In this work, a 3D/1D S-scheme heterojunction, integrating 2H-MoSe2 nanoflowers and TCPP porphyrin nanofibers, was synthesized via a scalable non-covalent self-assembly approach. Structural characterization reveals that the hierarchical MoSe2 architectures, composed of ultrathin nanosheets, are intimately coupled with π-conjugated porphyrin networks, resulting in a nearly three-fold increase in specific surface area (84.96 m2 g-1) relative to pristine MoSe2. Detailed band alignment analysis confirms a pronounced interfacial electronic reconstruction and the establishment of a built-in electric field, characteristic of an S-scheme configuration. Under simulated solar illumination, this configuration promotes the selective recombination of lower-energy carriers, effectively preserving highly reductive electrons in the LUMO of TCPP and highly oxidative holes in the valence band of MoSe2. Consequently, the optimized heterostructure exhibits significantly accelerated oxygen evolution reaction (OER) kinetics characterized by a low Tafel slope of 101 mV dec-1. This work presents a strategic design of S-scheme photocatalysts for efficient hydrogen evolution, providing a robust pathway toward sustainable solar fuel production.